How to configure a router for MSN Internet Access?

I am not sure if my question is addressed to the correct forum, but...

I have Gigafast EE400-RP router with a print server for my home LAN. It works fine, but I would be more happy if it does one more thing: I would like to setup its RS232 port with an external dial-up modem connected to it to go to MSN Internet Dial-up Access...

I know MSN has a special software for MS Windows only, to let you sign up and choose phone number etc, but this software is not nessesary to dial-up the service after you have the account already. I have already tested pure MS Dial-up Networking on my Windows 98 proving it works without MSN software - it is enough to give you login as "MSN/username", password and dial up to one of the given numbers... It connects, everything works great! :D

I tried to do the same with my router - I have set up login/password and the phone number. I have left IP and both DNS empty (0.0.0.0) to let it get numbers from the server but I have no luck connecting. Routers attempts to dial, modems negotiate fine but process does not finish with any success. After a while router shows status: failed.

What shoud I do? Does anybody tried to use a router to dial-up to MSN? What could be a reason for the failure? Does MSN detect non-Windows machine in the router somehow? :confused:

Greetings to all!