Asterisk to Avaya Index 200

Hello to all, I hope that this is in the correct place.

I have a system here that consists of an AVAYA INDEX 200 Digital PBX connected to our local telephone system VIA a British Telecom ISDN with 19 active channels, I also have a Swan Callview Server and Client and a SELTEK SDX Lite (that has just died on us). Hence the reason for the aterisk box being tinkered with.

My question is does anyone no how i can setup up the system so that i can use the power of the digital system and the digital phones to use the voice mail, IE our voicemail at the moment is on EXT 555, 556, 557, 558.

The card that is in the seltek at the moment is from BROOKTROUT and is RDSP-9X32-I not sure if this has Linux drivers but hopefully it has.

Any help would be greatly apreciated as i would then be able to expand the asterisk to other sites