replace:
			/* We create a fake call-id which the phone will send back in an INVITE
			   Replaces header which we can grab and do some magic with. */
			ast_str_append(&tmp, 0, 
					"<dialog id=\"%s\" call-id=\"pickup-%s\" direction=\"recipient\">\n"
					"<remote>\n"
					/* See the limitations of this above.  Luckily the phone seems to still be
					   happy when these values are not correct. */
					"<identity display=\"%s\">%s</identity>\n"
					"<target uri=\"%s\"/>\n"
					"</remote>\n"
					"<local>\n"
					"<identity>%s</identity>\n"
					"<target uri=\"%s\"/>\n"
					"</local>\n",
					p->exten, p->callid, local_display, local_target, local_target, mto, mto);
		
with:

			/* We create a fake call-id which the phone will send back in an INVITE
			   Replaces header which we can grab and do some magic with. */
			ast_str_append(&tmp, 0, 
					"<dialog id=\"%s\" direction=\"recipient\">\n"
					"<remote>\n"
					/* See the limitations of this above.  Luckily the phone seems to still be
					   happy when these values are not correct. */
					"<identity display=\"%s\">%s</identity>\n"
					"<target uri=\"%s\"/>\n"
					"</remote>\n"
					"<local>\n"
					"<identity>%s</identity>\n"
					"<target uri=\"%s\"/>\n"
					"</local>\n",
					p->exten, local_display, local_target, local_target, mto, mto);