strip domain name from username

[mailsubs]

I have freeradius 1.0.1 setup and working great except for authenticating to our windows domain.  With ntlm_auth from the command line I can authenticate fine.  Samba is installed and I have joined our local Windows 2000 domain.  I am using freeradius to authenticate wireless users via PEAP.  The problem I am having is that XP sends the username as “domain\username”.  If I uncheck the option in the XP wireless properties so that XP will not automatically authenticate with my cached credentials but instead prompt me for my login credentials it works fine as long as I do not enter a domain name.   How do I strip off the “domain\” from the “domain\username” so that my users won’t have to enter their login credentials a second time?  I’ve tried using the hints file and realms, but I’m having no success as I really don’t have a clue what I’m doing.       Any help would be greatly appreciated,   Brian