Or if you're truly masochistic you can try the monitor_early_media_fail_xxx chan vars. :)
-MC

On Mon, Feb 14, 2011 at 3:51 PM, Anthony Minessale <anthony.minessale@gmail.com> wrote:
you are better off using ignore_early_media=true so the originates
fail.  When you allow early media, getting early media counts as
success. When you are chaining many like that you can use artificial
ringbak by setting the variable ringback to ${us-ring} on the A leg.