pbx1> diff -uN a/channels/chan_sip.c b/channels/chan_sip.c 
--- a/channels/chan_sip.c       2011-06-03 03:01:10.000000000 -0400
+++ b/channels/chan_sip.c       2011-06-03 03:02:52.000000000 -0400
@@ -25150,6 +25150,9 @@
        if (!ast_strlen_zero(peer->fullcontact))
                ast_string_field_set(p, fullcontact, peer->fullcontact);
 
+       if (!ast_strlen_zero(peer->fromuser))
+               ast_string_field_set(p, fromuser, peer->fromuser);
+
        if (!ast_strlen_zero(peer->tohost))
                ast_string_field_set(p, tohost, peer->tohost);
        else