VLAN split / trunked - Preferred connection conflict. Need help.

Hey fellas,

I have an unbelievably troublesome issue... and haven't been able to find any support or documentation to help sort it out. Here's the situation:

Our office is decked out with soft phones, and to make sure that voice traffic is properly recorded and unimpared... we trunk the ports, and using Intel Proset's advanced features... we split the connection over two VLANs.

This way we can tell the soft phones which network interface to use... eg: Connection 4 10.10.120.123

And an untagged connection, where all traffic should be routed through, unless otherwise specified ... such as the soft phone application being able to manually point to using connection 4. We'll say this untagged DATA connection... is Connect 3 @ 10.10.12.123

On Windows XP.... NO ISSUES. Works brilliantly! And you set the network priority under advanced features on your adapter page... moving your 'DATA' connection up to the top of the list.

On Windows 7... I have one machine no issues... and one... where there's mental trouble.

The Priority: If we can't get this issue narrowed and resolved without relying on rebuild... we're not prepared to migrate the office to 7.

The issue: Both the DATA and SOFTPHONE connections (4 & 3) are listed as 'Preferred'.

This 'Preferred' bit in Windows 7 is killing me!! - It seems traffic is trying to route over both adapters... and so it fails. Can't hit a single msn.com or google page. Sometimes one will half-load... text only and a few boxes. If I disabled the SOFT connection, smooth... no issues... everything runs on DATA and loads.

BIG QUESTION: How the hell can I tell one of these connections to stop being preferred? Any Wizards here know any reg pointers even? Perhaps? Any help at all you guys can offer would be really HUGE.

Thank you for reading. We really appreciate it.