Trouble getting wireless connection before logon screen.

Hi I am having trouble getting computers to log into a domain via a wireless
network. I have set the network up as follows.
Wireless access points with WPA2-Enterprise encryption. Authentication has
been setup to use EAP-TLS with auto-enrolling certificates via group policy.
Client machines are Windows XP SP2 with the WPA2 fix applied. The servers
are all Windows 2003 SP1.

My problem....
I can log into an account with cached credentials and the wireless network
will work fine. However I cannot log into the domain with non-cached
credentials, ie. I am not getting connection via a computer certificate
before the login screen. I have tried the AuthMode=2 reg modification to
force computer certificates. From this I can see that as soon as a
cached-credentials user logs in the wireless network connects (there must be
a computer certificate on the machine to allow this) however when trying to
log in with a 'fresh' user account I cannot access the wireless network.

Does anyone have any ideas where Im going wrong.

Thanks
Jonathan

I am testing out new flat panel PCs with the Atheros AR5006EG wireless. I had pre logon connection working, though I am not sure how, up until yesterday. For some reason now, the wireless will not connect before the logon screen anymore. Now the accounts must be cached. I had AutoAdminLogon=1 with a particular account, and I once held the shift to force it to not login, so I could login as a different account. I believe that is when it stopped working. I get this damn strange feeling that it has something to do with a registry setting that is telling it to authenticate and connect before logon. If you have found any solutions to this or any ideas, please let me know.