Active Sync problems using RNDIS

I use a number of machine on a day to day basis, one of my development machines refuses to connect using Vista's Active Sync (Windows Mobile Device Center) to any devices using RNDIS as the connection type. The RNDIS connection is made but the device center refuses to attempt any connection... ger!

Connecting using USB serial works without any problems, so here is my work around until I find a fix:

If you are using Windows Mobile Standard (Smartphone) then you can switch to using USB Serial from the default that is RNDIS by going to settings->connections->USB to PC and un-selecting the "Enable advanced network functionality". This resorts to using the old fashioned USB serial. There should be a similar setting on Windows Mobile Professional (PocketPC).