Kerberos/Cups

[daniel]

Well I have CUPS running smoothly in my machine except when I tried to enable Kerberos auth. Probably cause I don't have enough Kerberos knowledge, anyway I have kinit running and tokens being granted through a server/realm that is not mine.
I do DefaultAuthType Negotiate and add AuthType Default and Require valid-user as is in the documentation. The client has a token and I do lpr ou lp as I would usually do but the server gives:
cupsdAuthorize: No authentication data provided.
Do I need a local keytab file? or some other config?

any leeds would be important