I did a google search on that error message, and this turned up -
http://archive.apache.org/gnats/1666
Any chance your customer is running Apache?
My only other suggestion is that it might be time to invole JTAC. This doesn't look like a usage question - it might be a bug.
Thanks for that. But it does sound more like an Apache bug than a Juniper bug, doesn't it? If Apache is only accepting "Basic" but not "basic" or "BASIC" or whatever, then this - I would say - is an Apache problem.
Or is it defined somewhere that the auth scheme token must be case sensitive?
Sascha