This is an issue I have fought with because of the use Novell. You have to login to the workstation first, then the wireless, then Novell. Novell is expecting a network connection to talk to the Tree, if it is not there, you won't be able to connect. There is a product that Novell has, I can't remember the name, but it is similar to single sign-on. I haven't had a chance to play with it, but according to my Novell engineers, it should work. It basically cache's all the creditentials, and then logs in.
I use PEAP-GTC to authenticate my users against the Novell LDAP. I have an ACS to do this.
Hope that helps.