NTFS permissions are still set the same way, domain or no. Your problem is that in a workgroup setup, each machine maintains it's own set of accounts and no machine trusts the accounts of another. So... I still have no idea what a web service has to do with this or what you're ultimately trying to accomplish. Your description doesn't make much sense.
A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007, 2008