asterisk users - May 2011 - Mitel PBX caller id format?

I'm setting up an asterisk server to extend several extensions from a mitel
pbx.

I'd like to display the caller id that I receive from t he mitel pbx
on the sip phone. The mitel
PBX person has setup the PBX to send be callerid, but I don't see it.

I've set chan_dahdi up with
usecallerid=yes
cidstart=ring
cidsignalling=bell
callerid = asreceived
cid_rxgain = 0.0

Are there specific settings for receiving the callerid from a mitel
pbx, or does something need
to be changed on the PBX to send the callerid in the appropriate format?

Thanks