File Field Handler - Thoughts?

I was playing around with Multiforms, as it's almost perfect for something I'd like to implement on a site or two. I had a bit of a go at creating a file field handler, but a small problem pops up when trying to save the file as FormsAPI or the file module (not sure which - as I didn't pick things apart that thoroughly) rewrites the name of the field to 'files['multiforms'] and thus nothing gets passed to the expected $field_values array.

Any ideas I might be missing on passing the info found in $files array to Multiforms? While I certainly haven't picked things apart thoroughly, I feel like I'm missing something rather obvious here...