asterisk users - Mar 2007 - Siemens HiPATH 3700 with Asterisk

Hi,

I will like to know if anyone would guide me about how I can to interconnect
one SIEMENS HiPATH 3700 with Asterisk.

HiPATH have VoIP card and my idea is to do one un IP trunk between them so
we would to transfer calls and services (voicemail, IVR,..) between both.

We havent PRI ports unused in HiPATH so cheapest method of interconnection
is one IP trunk.

Any help or comment about will be interesting.

Thnks in advance