asterisk users - Feb 2006 - Can Asterisk and new ShoreTel 6 talk to each other?

I've been anxiously awaiting ShoreTel version 6 because of it expanded
use of SIP.  My plan was to upgrade out ShoreTel server at our main
office to version 6, and use Asterisk in our small remote offices, and
have them all be able to directly dial each other's extension.  (i.e.
CEO in main office can dial ext 401 and get directly to secretary at
small remote office, and vice-versa)

However, this version of ShoreTel only uses SIP for trunks.  SIP
extensions are "not currently supported".  Am I banging my head
against
the wall trying to make this current version of ShoreTel work?   The
closest I've gotten to the Asterisk server talking to the ShoreTel
server is by watching Ethereal on the Asterisk server, and I can see
that the Asterisk server sends the INVITE, but the ShoreTel switch sends
back a "SIP Status: 404  Not Found".  Close, but no cigar.  :)

Anybody got any helpful thoughts or suggestions?

Thanks!!

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  - Jimmy Madden
  - Network Administrator
  - Health Services, Inc.
  - Montgomery, AL 36104