Incompatibility with webfm inline files and private file downloads

I'm using Print with webfm and private file downloads which is causing issues.
Essentially webfm obscures the URL for security purposes with the effect that _print_pdf_file_access_images() cannot get the file path from converting the URL.
This is similar to http://drupal.org/node/1333582 where you identified that without private file downloads the URL can be used (by not enabling use local paths), but this fails in my case as it will always convert private to local paths.

I can address this by checking for webfm paths, calling the file details and permissions check from webfm and then returning the correct file system path. I'm assuming however you're not going to want this in your codebase, so I was hoping you would be happy to enable a hook so that I can submit a patch to webfm to address the issue (or put in a custom module if necessary).

I've only really worked with using rather than invoking hooks before so I would appreciate it if you would advise where you would like it, then I'll have a crack at the development.