[Exim] auth relay

Hi, I am currently moving our mail system from postfix over to exim and I've hit a problem.

We have a number of customers using WAP and other such systems which aren't in our local IP address range. Under postfix we
got around this by allowing users to send from a given IP address after that user had authenticated with the pop3 server.

This was done with a package called DRAC which we patched in to our pop server (cucipop) and it generates a list of allowed
IP addresses in a file that postfix then reads to find out weather that IP is allowed to relay or not.

Can I do something similar with exim, or does exim have support to work with DRAC?

Any info will be most helpful.

Thanks

From Mitchell