Windows 7: Cannot get WP-S1 3G phone working as a modem in Windows 7 - Error 623

(cross-posted from Microsoft TechNet - apologies to those who read both sites)

I have an Amoi WP-S1 3G mobile phone (a.k.a. 3 SkypePhone). It comes with 32bit WinXP driver and application CDROM that includes a modem driver and modem client app. I have successfully installed and used them on XP Pro.

In Windows 7 32bit Home Premium, I can successfully install all drivers and apps from the CD. The PC-Synch app works but the Modem app cannot connect. The modem app opens OK and identifies the WP-S1 as an available device, but when I hit the Connect button, I get:

"The system could not find the phone book entry for this connection.error code is:623"

What I have tried so far:
- Closing my WiFi connection first
- Uninstalling all of the WP-S1 drivers (which were found automatically in Windows 7) and reinstalling from my CD-ROM
- Create a dial-up connection in Windows 7 Network Centre using the phone number from the WP-S1 modem app Settings window (*99#), leaving the username/password blank as it is in the WP-S1 app Settings.

When I got it going on WinXP, I did nothing special; it just worked.

Googling error 623 suggests that there might be some connection missing in the Windows 7 Networking Center that can be added (hence my attempt at creating a manual dialup connection).

Other details:
- In Windows 7 Devices, I have no unidentified devices - all correctly installed
- My computer is an ASUS T91MT tablet netbook running Windows 7 Home Premium
- My phone is connected by USB, although I hope to get bluetooth working next. I have also tried bluetooth, but the Modem App doesn't even find the phone.

I am tempted to try XP Mode, but I have only a 32GB SSD and an Atom Z520 CPU - I have neither space nor grunt to run virtual XP unless I start offloading a bunch of Program Files to an SD Card.

Hope someone can help. Thanks in anticipation.

Follow up: finally managed to get it working in Windows 7. When I install the modem client in XP, it also creates an XP dial up network connection. In Windows 7 it did not create the network connection. I had a couple of attempts to manually create the Dial-up Network, but it did not correctly identify the Modem. I don't really know what I did differently, but today when I tried to create a dial-up connection, it found the modem successfully.

I set all the settings in the dial-up network the same as XP and then tried dialing directly from XP - without the supplied client app. It failed a few times, but after a reboot it worked.