One way that I know of is if you clone the Upload File control (create a complete copy of the existing one) then add some code like a
SaveBizFormFile method that manipulates the the incoming posted file from the Raw Request. It would be an effort though, and definitely fully custom.
A second choice would be to write a Global Event handler, wait for the BizFormFile to get to its normal place on a standard form submit event, and after the standard submit is complete, then attach some code that moves the file to the place you want it.
Neither are totally great option to be honest.