Index: asterisk-1.6.2.7/channels/chan_sip.c
===================================================================
--- asterisk-1.6.2.7.orig/channels/chan_sip.c	2010-05-12 11:33:21.000000000 +0100
+++ asterisk-1.6.2.7/channels/chan_sip.c	2010-05-12 17:49:28.000000000 +0100
@@ -20377,6 +20391,7 @@
 
 			/* Let the caller know we're giving it a shot */
 			transmit_response(p, "100 Trying", req);
+			p->invitestate = INV_PROCEEDING;
 			ast_setstate(c, AST_STATE_RING);
 
 			/* Do the pickup itself */