Login Script – Group Policy – Map %USERNAME% to Folder

I have a situation I can’t figure out the best way to handle. Running WinXP user machines and Linux server. Using NTConfig policy to manage default settings for logging into our domain. Each User has My Documents folder located on Server, and want most of workstations to automatically map the My Docs Folder by default to the Network Location, however I can’t use the NTConfig.POL because it doesn’t allow you do do this and at the same time allow some users to not automatically map that folder. So Is there anyway I can create a login script on the local machine to Automatically map the %USERNAME%\My Documents folder to my server? And have it work if users sign it at different locations automatically? HELP.
Thanks
Drew