asterisk users - Oct 2003 - Setvar SIP_CODEC

Hello,
	I have 
a couple of 7960 and a quad T1 card on my asterisk box. I want to let
the phones to use g729 when they "talk" to each other, but to use g711
when I'm going to route the call out of my network using the T1 card. 
	Everything works just fine between the phones, but in order to be able
to make calls through T1 I have to disallow the g729.

	For this purpose I have the following configuration using yesterday's
cvs.

[sip.conf]
disallow=all
allow=g729
allow=ulaw

[extensions.conf]
exten => 123456,1,SetVar,SIP_CODEC=ulaw
exten => 123456,2,Dial(${TRUNK}/${EXTEN})

	The problem is with the SetVar function, the debug shows that the
function is executed, but after that, * sends the media capability to
the phone with g729 as preferred codec.

	Is there any work around? or simply setVar wasn't meant for this
scenario.
	
	Thanks  

-- 
Luis Benavente <luisbe@bts-usa.com>

> [extensions.conf]
> exten => 123456,1,SetVar,SIP_CODEC=ulaw
> exten => 123456,2,Dial(${TRUNK}/${EXTEN})
>
> 	The problem is with the SetVar function, the debug shows that the
> function is executed, but after that, * sends the media capability to
> the phone with g729 as preferred codec.
SIP_CODEC is was supposed to only change the codec of the incoming call,
eg: asterisk responds with ANSWER with ulaw codec ...

But it won't change anything with the 2nd call.

regards
Martin