InfoPath Dev

I published an InfoPath browser-enabled form to a SharePoint document library.  When the user opens the form and submits it, it needs to have the capability to be opened up by either the same person or someone else for updating.  How can I keep the original form that was submitted in the library, but there be versions of it along the way?

The simplest answer would be to turn on versioning for the form library. But if you want them all available in the library at the same time, you could just modify the file name on each submit to create a new XML file - then you have to worry about people opening / updating the correct one, of course, so that may be icky.