PDF Document Revisions

OK, we are creating a number of customer files (pdf) outside EPDM. The document files are all named the same but they are different revisions. This morning I vaulted a new revision of the file and it overwrote the existing version. I was hoping it kept a(n) historical copy of the old revision. It did not. So, this leads me to my question; If a file is loaded into EPDM and another revision is sent can I save both files under the same document name? We will need to be able to pull these old revisions in their entirety at a later date for tracking purposes. Or, do we just save each file into EPDM and add the "REV" to the filename...

Thanks,

SolidworksSolidworks Pdm enterprise Pdm