Trouble with configuring a PAP2

I’m having no luck with this

From my PAP2, I can make and receive calls to anywhere EXCEPT to any DIDs that are on my asterisk box

the PAP2 can even make extension to extension calls successfully

but when I dial a number over my Vitelity (or any other) trunk with the PAP2, I see the SIP 486 busy message in the CLI

if I dial a DID on the asterisk box with X-Lite or Idefisk, it goes out through the vitelity (or any other) trunk and behaves normally

For this reason I feel it’s a PAP2 problem… does anyone have any clues as to how I can fix this?

My PAP2 configuration is here (i posted the entire pap2 interface online)
http://www.fobiopatel.com/dongles/

I have a SIP and IAX username and password you can use to connect to my server, my contact details to get these are:

aim: fobiopatel
msn: [email protected]
yahoo messenger: [email protected]
google chat: fobiopatel

Thanks so much!!