Documents signed outside of the system

Our organization is utilizing Adobe Sign for eSignature in Supplier Contract Management. We are running into issues where at times the outside party will print and sign the document during the external review process prior to being routed for eSignature. The problem we are experiencing is when the document is signed, it comes back to us in a .pdf format. Since the document was generated using the document configurator, the system will only allow for an .xml file to be uploaded back into the system. We have tried workarounds such as converting the document into a word file, but this