Windows 7: cannot reconnect drives to Mac OS X -connects first time though

One of our users has a Windows 7 profesional 64 bit new computer. He always used to SMB shared drives on a Mac where he saves some art work. And it worked fine with XP and Vista.
We operate currently under a 2003 domain. To make the situation clearer I will use some made up names: DOM would be our domain, John Smith is the user and his Mac computer is called johnmac and the local username for mac is johnsmith. Mac OS X is not under the domain and I think he uses sharepoint to share drives as SMB shares.
So when we type \\johnmac and hit enter on search box we get a prompt for the username and password. He types johnsmith as username and supplies the password (you can see that the domain name is DOM on the credentials box) and clicks on the box to save credentials and then we map the shared drives with the credentials already supplied and check "Reconnect at logon". Everything works great
On the Credentials Manager I see under windows credentials the username johnsmith, the password in asterisks and domain as DOM.
We restart the computer and it does not reconnect the mapped drive. It tries but it says it could not reconnect all drives. When you double click on the x drive, it tries to connect and it says something like username not found. But it does work the first time though and that is very weird. I am completely lost. Please any help is greatly appreciated.
Also how could I force the credential manager to save it as a generic credential instead of windows credential. There is no choice when you save the credentials. I tried to enter generic credentials but that did not help. I still had to enter credentials manually.
I don't want to use a batch file with net use as it would expose the password of the user.
Every other windows 2003 or Vista drive maps fine.