asterisk users - Jan 2007 - Getting two Asterisk machines to talk to each other

I want to do something that seems like it should be very simple.  Then 
again so am I ;)

Anyway, I have two asterisk boxes on separate subnets.  What I want is 
for a certain extension 3053 when dialed on the main machine to ring 
through to a SIP phone that is registered on the other Asterisk 
machine.  I'm sure the information is out there I just can't seem to 
concoct the proper search string to find it.

This is what I've tried:

I have created a peer entry for each machine in the other's sip.conf
I have changed the extension so that when it is dialed on the main 
machine it does the following
    Dial(SIP/test-machine/3053)    I feel this is most likely my problem.
The other machine has the same generic setup as the first (copied config 
files) with the exception of 3053 ringing the phone and the peer 
definition in sip.conf of course.

When I tried calling the extension via the main machine it simply rang 
to voicemail.

Any help would be appreciated.  Thanks.

-Glen