I've dropped the unnecessary quotes as you suggested. I have a really stupid question though: where do these constants derive their values? I wanted to see what their values were, so I printed them out, and got this:
key DisplayType=3
key Scope=3
key Type=1
key Usage=2
I had a look at the FileOp module, and it looks like it would do just what I need. Unfortunately, it takes an act of congress to deploy a module that isn't part of the standard install around here -- so I'll get the paperwork started. By the way didn't you write FileOp?