Mapped drive disconnect - Windows 7

Question

You may be aware that mapped drives a discionnected on Windows 7 after some time.

This is a problem for us because our build machine is a windows 7 machine accessing network drives.

We have ttried http://support.microsoft.com/kb/297684#LetMeFixItMyselfAlways and this has not resolved the issue.
Overnight the drive is disconnected. Note: No changes have been made of the server side.

This is likely to be a client side issue, as the 2003 file servers work fine under XP but disconnect on Windows 7.
This causes our builds to fail. Note: While using Explorer you get an automatically connect, and even using a CMD window the system re-connects automatically.

However within the context of a build rule inside Visual Studio it does not re-connect, hence the copy fails.

>> Can you suggest another setting change to force windows to to disconnect mapped drives ?

Thanks