--- chan_sip.c	2012-02-22 15:14:31.000000000 +0100
+++ chan_sip.c	2012-02-22 15:20:00.000000000 +0100
@@ -11832,7 +11832,9 @@
 			l = CALLERID_UNKNOWN;
 			n = l;
 			d = FROMDOMAIN_INVALID;
-		}
+		} else if (ast_test_flag(&p->flags[0], SIP_SENDRPID))  {
+                        n = p->fromuser;
+                }
 	}
 
 	/* Hey, it's a NOTIFY! See if they've configured a mwi_from.