Dial Up Server problem

I have the following problem when trying to configure RAS Server for remote dial up Server:

1. I have configured three modems and install their drivers and they are working correctly without any conflicts.

2. I have started and configured RAS Server for dial up server

3. i can only see one modem in the ports, and the other modems are configured but not appeared in the ports.

4. when starting the RAS Server and trying to queri the modems only the available modem passes the test and the others appears as conflict, and when stopping the RAS, all modems pass the test

5. The three modems are in different supported types

6. i tried the issue on Windows 2003 SP1, Windows 2000 AS SP4