Need help on configure asterisk

dear members, preety much noob here,

I need some help on installing asterisk on centos 5.5 dedicated server. I already install asterisk 1.8 latest, anyway.
But my problem is my routing. My route is softswitch (Voss / vsr) to Asterisk (dedicated server) to remote pc (On dynamic IP and running ubuntu / ylmf)
here the problem: switch - Asterisk server will use sip, Asterisk server to Asterisk Client server will use IAX2 for (limited bandwidth and nat issue).

I have those remote server configured (running on ylmf with svn-branch, asterisk renamed to SBO) , and switch to Asterisk server connected via sip, but cant pass the calls sip to IAX or to my remote client. I wanna use g729 ang g723.1 as default codecs for limited bandwidth etc.

Is there any one who can help me for this matter. I will pay if it works. thank you.

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Can you please copy/paste the Asterisk CLI output of the failing SIP - to - IAX2 call?