Index: telepathy-sofiasip-0.6.3/src/sip-media-session.c
===================================================================
--- telepathy-sofiasip-0.6.3.orig/src/sip-media-session.c	2012-09-16 11:37:01.973187745 +0200
+++ telepathy-sofiasip-0.6.3/src/sip-media-session.c	2012-09-16 11:42:06.207738910 +0200
@@ -143,6 +143,7 @@
   sdp_session_t *backup_remote_sdp;       /* previous remote session */
   GPtrArray *streams;
   gboolean remote_initiated;              /*< session is remotely intiated */
+  gboolean invite_3pcc;                   /*< did we receive a 3pcc invite? (or normal) */
   gboolean accepted;                      /*< session has been locally accepted for use */
   gboolean se_ready;                      /*< connection established with stream-engine */
   gboolean pending_offer;                 /*< local media have been changed, but a re-INVITE is pending */
@@ -771,6 +772,22 @@
 }
 
 gboolean
+tpsip_media_session_get_invite_3pcc (TpsipMediaSession *session)
+{
+  TpsipMediaSessionPrivate *priv = TPSIP_MEDIA_SESSION_GET_PRIVATE (session);
+  return priv->invite_3pcc;
+}
+
+void
+tpsip_media_session_set_invite_3pcc (TpsipMediaSession *session,
+                                     gboolean state)
+{
+  TpsipMediaSessionPrivate *priv = TPSIP_MEDIA_SESSION_GET_PRIVATE (session);
+  g_assert(priv->remote_initiated == TRUE);
+  priv->invite_3pcc = state;
+}
+
+gboolean
 tpsip_media_session_set_remote_media (TpsipMediaSession *session,
                                     const sdp_session_t* sdp)
 {
@@ -1090,6 +1107,14 @@
 
   priv->accepted = TRUE;
 
+  if(priv->invite_3pcc && !priv->streams->len)
+    {
+      /* We've received a 3pcc INVITE and have no media at all.  Simply trigger
+       * creation of a audio stream locally and propose that. */
+      tpsip_media_session_add_stream (self, TP_MEDIA_STREAM_TYPE_AUDIO,
+          TP_MEDIA_STREAM_DIRECTION_BIDIRECTIONAL, TRUE);
+    }
+
   /* Apply the pending send flags */
   priv_apply_streams_pending_direction (self,
       TP_MEDIA_STREAM_PENDING_LOCAL_SEND |
@@ -1783,6 +1808,15 @@
 
   g_return_if_fail (priv->nua_op != NULL);
 
+  if (reinvite && priv->invite_3pcc && priv->remote_sdp == NULL)
+    {
+      /* We don't send the INVITE here since we're still in call setup phase
+       * (this is we did not yet ack the incoming connection).  Otherwise
+       * this would lead to an outgoing call. */
+      DEBUG("defering INVITE during 3pcc call setup phase");
+      return;
+    }
+
   user_sdp = g_string_new (NULL);
 
   if (priv_session_local_sdp (session, user_sdp, TRUE))
@@ -1822,7 +1856,7 @@
 
   user_sdp = g_string_new (NULL);
 
-  if (priv_session_local_sdp (session, user_sdp, FALSE))
+  if (priv_session_local_sdp (session, user_sdp, priv->invite_3pcc))
     {
       msg_t *msg;
 
Index: telepathy-sofiasip-0.6.3/src/sip-media-channel.c
===================================================================
--- telepathy-sofiasip-0.6.3.orig/src/sip-media-channel.c	2012-09-16 11:37:01.985188643 +0200
+++ telepathy-sofiasip-0.6.3/src/sip-media-channel.c	2012-09-16 11:37:30.753190851 +0200
@@ -1356,9 +1356,15 @@
       if (tpsip_media_session_get_state (priv->session)
           != TPSIP_MEDIA_SESSION_STATE_INVITE_RECEIVED)
         break;
-      if (r_sdp != NULL)
+      if (r_sdp == NULL)
+        {
+          DEBUG("flagging incoming call as 3pcc INVITE'd");
+          tpsip_media_session_set_invite_3pcc (priv->session, TRUE);
+        }
+      else
         priv_initial_media_properties_from_sdp (self, r_sdp);
       g_signal_emit (self, signals[SIG_INCOMING_CALL], 0);
+
       break;
     case nua_callstate_proceeding:
       switch (status)
Index: telepathy-sofiasip-0.6.3/src/sip-media-session.h
===================================================================
--- telepathy-sofiasip-0.6.3.orig/src/sip-media-session.h	2012-09-16 11:37:01.965196575 +0200
+++ telepathy-sofiasip-0.6.3/src/sip-media-session.h	2012-09-16 11:37:30.753190851 +0200
@@ -77,6 +77,9 @@
 TpsipMediaSessionState tpsip_media_session_get_state (TpsipMediaSession *session);
 void tpsip_media_session_change_state (TpsipMediaSession *session,
                                      TpsipMediaSessionState new_state);
+gboolean tpsip_media_session_get_invite_3pcc (TpsipMediaSession *session);
+void tpsip_media_session_set_invite_3pcc (TpsipMediaSession *session,
+                                          gboolean state);
 gboolean tpsip_media_session_set_remote_media (TpsipMediaSession *chan,
                                             const sdp_session_t* r_sdp);
 TpsipMediaStream* tpsip_media_session_add_stream (TpsipMediaSession *self,