Sarian ISDN Modem Driver for Win 7 64-bit

Our company is now using Win 7 64-bit. We use a Sarian IR2140 to remotely connect to our customers using a RAS connection. To do this we have to install the Sarian as a ISDN modem driver using the Sarian Multi-port driver but we have tried using this but this driver is only for 32-bit Operating Systems.
Does anyone know a way round this or if there is a generic 64-bit ISDN modem driver we can use?
The only idea I have is to run a 32-bit Virtual PC on the laptop and use this to remote connect.

Thanks in advance for any help

you could use the microsoft standard modem 33k or 56k

in device manager at the top of the tree add legacy hardware

Hope that helps