[Asterisk-Dev] Adding Q931 cause codes to IAX2/SIP

[Maxim Litnitsky]

Hello dear developers.
Why not pass ISDN Q931  Cause codes to IAX2 and SIP?
I have to * boxes in IAX2  trunk and would like to see EXACT cause why
somebody cannot reeach the other party.
What r the reasons not to pass ISDN Q931 cause codes? 
Hope some of you will spend 2 minutes and answer me because googling
mailing lists does not help.

http://www.google.com/search?hl=en&q=site%3Alists.digium.com++iax+q931+cause&btnG=Google+Search