Problem linking a RAPI file handle

I'm working with a desktop API to build a desktop application that only
takes character strings to reference file names. But, I'd like to use
RAPI to access a file handle and hand it off to the desktop API. Is
there a way to do this?

1. I don't want to copy the entire file on the handheld off to the
desktop since some files will be relatively large.

2. Is there a literal string name that can be used to reference files
on the handheld (maybe there's a special handheld file prefix)?

.