Hello Jens (and other lispworks users),
I finally got a chance to do some coding, and I pushed a patch that should fix this problem -- could you try it out and tell me if it works at all. The only lisp interpreter I had available was Franz' telnet repl, so testing has been minimal, but the changes weren't that drastic, so there is a not unreasonable chance that they are correct.
Cheers, Marijn