diff --git a/core/AmApi.cpp b/core/AmApi.cpp
index 9ea2c0c6..3d3f4af6 100644
--- a/core/AmApi.cpp
+++ b/core/AmApi.cpp
@@ -104,3 +104,11 @@ AmCtrlInterfaceFactory::AmCtrlInterfaceFactory(const string& name)
   : AmPluginFactory(name) 
 {
 }
+
+AmCtrlInterface::AmCtrlInterface() 
+{
+}
+
+AmCtrlInterface::~AmCtrlInterface() 
+{
+}
diff --git a/core/AmApi.h b/core/AmApi.h
index 7f62b4c2..698acd89 100644
--- a/core/AmApi.h
+++ b/core/AmApi.h
@@ -235,17 +235,20 @@ class AmInterfaceHandler;
 class AmCtrlInterface: public AmThread
 {
  public:
-    AmCtrlInterface() {}
-    //virtual ~AmCtrlInterface() = 0;
-
-    //@param serKey An out parameter
-    virtual int send(const AmSipRequest &, string &serKey) = 0;
-
-    virtual int send(const AmSipReply &) = 0;
-
-    virtual string getContact(const string &displayName, 
-        const string &userName, const string &hostName, 
-        const string &uriParams, const string &hdrParams) = 0;
+  AmCtrlInterface();
+  virtual ~AmCtrlInterface();
+  
+  //@param serKey    [out] An out parameter
+  //@param serKeyLen [out] An out parameter
+  
+  virtual int send(const AmSipRequest &, 
+		   char* serKey, unsigned int& serKeyLen) = 0;
+  
+  virtual int send(const AmSipReply &) = 0;
+  
+  virtual string getContact(const string &displayName, 
+			    const string &userName, const string &hostName, 
+			    const string &uriParams, const string &hdrParams) = 0;
 };
 
 /**
diff --git a/core/AmServer.cpp b/core/AmServer.cpp
index 2bd4f308..05244ee8 100644
--- a/core/AmServer.cpp
+++ b/core/AmServer.cpp
@@ -62,9 +62,9 @@ bool AmServer::sendReply(const AmSipReply &reply)
   return ctrlIface->send(reply);
 }
 
-bool AmServer::sendRequest(const AmSipRequest &req, string &serKey)
+bool AmServer::sendRequest(const AmSipRequest &req, char* serKey, unsigned int& serKeyLen)
 {
-  return ctrlIface->send(req, serKey);
+  return ctrlIface->send(req, serKey, serKeyLen);
 }
 
 string AmServer::getContact(const string &displayName, 
diff --git a/core/AmServer.h b/core/AmServer.h
index e4c7ebaa..52dd97ad 100644
--- a/core/AmServer.h
+++ b/core/AmServer.h
@@ -66,7 +66,7 @@ public:
   void regIface(const AmCtrlInterface *i);
   bool hasIface() { return ctrlIface != NULL; };
 
-  static bool sendRequest(const AmSipRequest &, string &);
+  static bool sendRequest(const AmSipRequest &, char* serKey, unsigned int& serKeyLen);
   static bool sendReply(const AmSipReply &);
   static string getContact(const string &displayName, 
       const string &userName, const string &hostName, 
diff --git a/core/AmSipDialog.cpp b/core/AmSipDialog.cpp
index 8d913fc7..c6898fd0 100644
--- a/core/AmSipDialog.cpp
+++ b/core/AmSipDialog.cpp
@@ -40,6 +40,11 @@ const char* AmSipDialog::status2str[4]  = {
   "Disconnecting" };
 
 
+AmSipDialog::AmSipDialog(AmSipDialogEventHandler* h)
+  : status(Disconnected),cseq(10),hdl(h), serKeyLen(0)
+{
+}
+
 AmSipDialog::~AmSipDialog()
 {
   DBG("callid = %s\n",callid.c_str());
@@ -527,9 +532,10 @@ int AmSipDialog::cancel()
   req.callid = callid;
   req.cseq = cancel_cseq;
   //useful for SER-2.0.0
-  req.serKey = serKey;
-  string empty;
-  return AmServer::sendRequest(req, empty) ? 0 : -1;
+  req.serKey = string(serKey, serKeyLen);
+  char empty[MAX_SER_KEY_LEN];
+  unsigned int unused = 0;
+  return AmServer::sendRequest(req, empty, unused) ? 0 : -1;
 }
 
 int AmSipDialog::sendRequest(const string& method, 
@@ -584,7 +590,7 @@ int AmSipDialog::sendRequest(const string& method,
     req.body = body;
   }
 
-  if (AmServer::sendRequest(req, serKey))
+  if (AmServer::sendRequest(req, serKey, serKeyLen))
     return -1;
     
   uac_trans[cseq] = AmSipTransaction(method,cseq);
diff --git a/core/AmSipDialog.h b/core/AmSipDialog.h
index 3e0b0f3b..ca3bec84 100644
--- a/core/AmSipDialog.h
+++ b/core/AmSipDialog.h
@@ -35,6 +35,7 @@
 #include <map>
 using std::string;
 
+#define MAX_SER_KEY_LEN 30
 #define CONTACT_USER_PREFIX "sems"
 
 // flags which may be used when sending request/reply
@@ -137,12 +138,10 @@ class AmSipDialog
 
   int cseq;            // CSeq for next request
 
-  string serKey;      // opaque string returned by SER, when staring a T
-
-  AmSipDialog(AmSipDialogEventHandler* h=0)
-    : status(Disconnected),cseq(10),hdl(h)
-    {}
+  char serKey[MAX_SER_KEY_LEN];      // opaque string returned by SER, when staring a T
+  unsigned int serKeyLen;
 
+  AmSipDialog(AmSipDialogEventHandler* h=0);
   ~AmSipDialog();
 
   bool   getUACTransPending() { return !uac_trans.empty(); }
diff --git a/core/plug-in/binrpcctrl/BrpcCtrlInterface.cpp b/core/plug-in/binrpcctrl/BrpcCtrlInterface.cpp
index e5a95b01..148ebc3d 100644
--- a/core/plug-in/binrpcctrl/BrpcCtrlInterface.cpp
+++ b/core/plug-in/binrpcctrl/BrpcCtrlInterface.cpp
@@ -1120,7 +1120,7 @@ static inline brpc_t *build_request(const AmSipRequest &amReq,
   return req;
 }
 
-int BrpcCtrlInterface::send(const AmSipRequest &amReq, string &serKey)
+int BrpcCtrlInterface::send(const AmSipRequest &amReq, char *serKey, unsigned int &serKeyLen)
 {
   int ret = -1;
   brpc_t *req, *rpl = NULL;
@@ -1161,7 +1161,8 @@ int BrpcCtrlInterface::send(const AmSipRequest &amReq, string &serKey)
   }
   DBG("SER's opaque/reason: `%.*s'.\n", BRPC_STR_FMT(ser_opaque));
   //len must be fed, as the opaque could contain 0s
-  serKey = string(ser_opaque->val, ser_opaque->len);
+  memcpy(serKey, ser_opaque->val, ser_opaque->len);
+  serKeyLen = ser_opaque->len;
 
   ret = 0;
 end:
diff --git a/core/plug-in/binrpcctrl/BrpcCtrlInterface.h b/core/plug-in/binrpcctrl/BrpcCtrlInterface.h
index b8b642d0..e035cfcf 100644
--- a/core/plug-in/binrpcctrl/BrpcCtrlInterface.h
+++ b/core/plug-in/binrpcctrl/BrpcCtrlInterface.h
@@ -75,7 +75,7 @@ class BrpcCtrlInterface: public AmCtrlInterface
     void on_stop() {}
 
     // AmCtrlInterface
-    int send(const AmSipRequest &, string &);
+    int send(const AmSipRequest &, char *, unsigned int &);
     int send(const AmSipReply &);
 
     string getContact(const string &displayName, 
diff --git a/core/plug-in/sipctrl/SipCtrlInterface.cpp b/core/plug-in/sipctrl/SipCtrlInterface.cpp
index 990c9454..8a22c5c0 100644
--- a/core/plug-in/sipctrl/SipCtrlInterface.cpp
+++ b/core/plug-in/sipctrl/SipCtrlInterface.cpp
@@ -158,8 +158,10 @@ string SipCtrlInterface::getContact(const string &displayName,
 }
 #endif
 
-int SipCtrlInterface::send(const AmSipRequest &req, string &serKey)
+int SipCtrlInterface::send(const AmSipRequest &req, char* serKey, unsigned int& serKeyLen)
 {
+    serKeyLen = 0;
+
     if(req.method == "CANCEL")
 	return cancel(req);
 
@@ -269,12 +271,10 @@ int SipCtrlInterface::send(const AmSipRequest &req, string &serKey)
 	}
     }
 
-    char tid[12];
-
-    tl->send_request(msg,tid);
+    tl->send_request(msg,serKey);
     delete msg;
 
-    serKey = string(tid,12);
+    serKeyLen=12;
     return 0;
 }
 
diff --git a/core/plug-in/sipctrl/SipCtrlInterface.h b/core/plug-in/sipctrl/SipCtrlInterface.h
index ae33dec8..8eec49d2 100644
--- a/core/plug-in/sipctrl/SipCtrlInterface.h
+++ b/core/plug-in/sipctrl/SipCtrlInterface.h
@@ -81,8 +81,7 @@ public:
     /**
      * From AmCtrlInterface
      */
-
-    int send(const AmSipRequest &req, string &serKey);
+    int send(const AmSipRequest &req, char* serKey, unsigned int& serKeyLen);
     int send(const AmSipReply &rep);
     
 #ifndef _STANDALONE
diff --git a/core/plug-in/unixsockctrl/UnixCtrlInterface.cpp b/core/plug-in/unixsockctrl/UnixCtrlInterface.cpp
index de4f4642..11f519b9 100644
--- a/core/plug-in/unixsockctrl/UnixCtrlInterface.cpp
+++ b/core/plug-in/unixsockctrl/UnixCtrlInterface.cpp
@@ -130,7 +130,7 @@ int UnixCtrlInterface::init(const string& socket_name)
     return 0;
 }
 
-int UnixCtrlInterface::send(const AmSipRequest &req, string &_)
+int UnixCtrlInterface::send(const AmSipRequest &req, char *, unsigned int &)
 {
   return rplAdapt.send(req, reply_socket_name, ser_socket_name);
 }
diff --git a/core/plug-in/unixsockctrl/UnixCtrlInterface.h b/core/plug-in/unixsockctrl/UnixCtrlInterface.h
index c6c79eee..2cd5f21f 100644
--- a/core/plug-in/unixsockctrl/UnixCtrlInterface.h
+++ b/core/plug-in/unixsockctrl/UnixCtrlInterface.h
@@ -65,7 +65,7 @@ class UnixCtrlInterface : public AmCtrlInterface
     ~UnixCtrlInterface();
 
     // AmCtrlInterface
-    int send(const AmSipRequest &, string &);
+    int send(const AmSipRequest &, char *, unsigned int &);
     int send(const AmSipReply &);
 
     string getContact(const string &displayName,