Stored user names and passwords BROKEN in Vista

It seems that stored usernames and passwords no longer works in Vista (XP
works fine).

We use this feature to connect to SQL Servers using a particular UID/PW
combination so we dont have to use clear text authentication (i.e. SQL
Server Auth).

On XP we could create a wildcard domain and UID/PW and save it in "stored
user names and password" then the user could use for example iSQL or
Enterprise Manager to connect to the server via windows authentication.

If I try this with Vista it either sends my current domain id/pw OR (if
the machine is not in a domain) it seems to send NULL instead.

Anyone have any ideas on what/where something might be adjusted to fix this
issue ???