Easiest way to set this up is to have Avaya send calls direct to HMP/VoiceGuide's IP address. To do this you will need to set up a SIP trunk in Avaya, pointing to HMP/VoiceGuide.
Some information on this is done can be found online:
For Dialogic HMP software, the default RTP port range starts at 49152 for channel 1, 49154 for channel 2, and so on, following that sequence for the amount of IP channels on the system.
(RTP port range used can be changed in HMP config if needed)
Running WireShark (www.wireshark.org) on the HMP/VoiceGuide system will let you see the SIP packets exchanged. Specify this in WireShark's filter text box: sip
Please let us know if you have any questions.