How can I fix my sagging automobile ceiling upholstery?

I am the proud owner of a 1997 XJ6L Jaguar. A regular creampuff. But for the ceiling upholstery, which is beginning to detach from its moorings, and is sagging in the vicinity of the rear window. Is there a cheap, practical way of re-attaching the upholstery to the ceiling above, without suffering unsightly glue stains, etc? Or, do I have to re-upholster the entire ceiling (ugh).