IP over X25 without x.121

Hi all!

I may be OT, but someone may know the answer:

I need to connect my server (Linux of course) to some strange device.
The connection have to be done over TCP / IP / X.25 / LAPB / ISDN-BRA
I'd like to do it with cisco router. I've configured cisco L1 and L2 and
they are operational. I have problem with IP/X.25 layer - the device
operates in strange mode without X.121 address, so I don't know how to
configure X.25 - IP mapping.
Has someone any experience with X.25 ?

Jarek