Set up a Dial Up Connection - Modem not present

I am attempting to add a Dial Up Connection for use with a USB 3G Wireless
device (Novatel Wireless Ovation HSDPA Modem).

When I attempt to add a new Dial Up Connection using the Network and Sharing
Center, the first message I get is that Windows could not detect a dial-up
modem.

1. The Modem appears in the Device Manager list under modems. The Device
Manager informs me that the device is working properly.

2. The compter's built in modem also appears in the list. The Device
Manager informs me that the device is working properly.

3. I have downloaded and followed the Manufacturers instruction for
installation on Vista.

4. I have downloaded the latest drivers from the manufacturers website and
installed them and reinstalled them.

The USB Modem works fine on another non-Vista laptop (running Server 2008).

My question is why does the dial up not recognise that the modem is present.
Could this be due to my user permissions in Vista. Is there a setting that
I am missing to allow the modem(s) to be seen?

Thanks, J