asterisk users - Mar 2009 - place T1 calls and ignore/override call progress

Is there a way to make a call on a digital line T1/PRI
and dont WAIT for the signalling back that the call was answered?

I have a case where the T1 is working fine. I can dial work, numbers 
cell numbers etc...
everything is fine. EXCEPT when I dial this internal trunk to access a 
PA system.
The T1 is not telling me (in this case the line was answered) even 
though the PA system is
giving dial tone.

Is there anyway to tell the T1/PRI that as soon as I dial to just return 
the call was answerered?
so my AGI will start - I'll pulse out zone code digits and speak my message.

How can I do that?

Thanks,

Jerry