How to access Time Capsule with Windows XP

I'm in a similar boat with xp machine on a windows domain(for work).

I can't find by browsing the network but I can connect to it if I supply the ip address of the time machine \\xxx.xxx.x.x\data

When I set up the tc to allow guest access I can connect using the ip address but I'd rather not and use the TC password. Using the airport utility it finds the disk but when I supply the password it doesn't work

When connecting via windows \\xxx.xxx.x.x\data and not as guest I need a username/password. I'm thinking if I knew the username i would use that and the time capsule password?

Any idea what the username is? I'd really like to use the main user instead of setting up accounts on the time capsule.