asterisk users - Jan 2005 - IAX2 trunking, Voicepulse Connect, and Outbound Faxing

I've just stumbled across a rather weird problem and was wondering if 
someone could shed some light on the situation.

In testing faxing through Asterisk using Voicepulse Connect for 
trunking I am able to receive faxes without a hitch. Quite impressive 
considering previous experience with certain other VOIP providers. 
Today I finally got around to testing outbound faxing and found that if 
I have trunk=yes defined along with g.711 (ulaw), I am not able to send 
faxes out. I get a poor line condition, comms error, etc. If I turn 
trunking off the fax machines establish a connection quite readily and 
the fax goes through lickety split.

So how is it that with trunking on I can receive faxes but not send? 
Perhaps this is a Voicepulse bug?

And for anyone else wondering about Sixtel (iax.cc) faxing (at least 
outound) just doesn't seem to work at all through them. When a call 
connects you a hear a brief CNG tone and then the line goes silent. 
Maybe they have T.38 turned on.

-mark

--
Mark Eissler, mark@mixtur.com
Mixtur Interactive, Inc. -@- http://www.mixtur.com