Here's a patch to allow for completion in shortcut operations which deal with ASDF systems. It's sub-optimal because it only checks ASDF's central registry but I don't think it's possible to write a general solution in the presence of ASDF:*SYSTEM-DEFINITION-SEARCH-FUNCTIONS*.
I was about to write that I doubt anybody uses custom search functions anyway and that I myself had never heard of them. But then I remembered that I had:
http://weitz.de/asdf-install/#load-asdf-install
:)
Anyway, here's the patch.
Cheers, Edi.