ooh323 Trunk to provider... HELP!

Hi everyone I’m trying to set up a trunk to a provider who is running H.323. I’m running trixbox 1.1 and ooh323 is built into the system. I setup a custom trunk with dial string "OOH323/$OUTNUM$@xx.xx.xx.xx"
I also setup my ooh323.conf file as per the instructions within the file. When I try to dial out thru this trunk I get ringback tone but it keeps ringing and ringing. Anyone got any clues? I looked in the h323_log files and no errors. What am I doing wrong? Do I need to put anything into my extensions.conf file to dial out?