Hi Steve,
In order to change and update related documents in CaseComplete, it's a manual process. The software doesn't monitor for changes in documents that weren't created by CaseComplete.
Open your project and find the reference to your related document. You should see a lock icon next to it, indicating it's checked in with the version control system. (If it's not, send an email to support@serlio.com and we'll help you get it set up that way.)
Right-click on your Vision document (in CaseComplete) and select Check Out from the context menu.
At this point, open your external program and make a trivial change to the document in order for the version control system to recognize a change that needs to be committed, and save your file.
You can now check the document back in by right-clicking on the document and selecting Check In, or click Home / Check In on the ribbon bar. Notice that when your changes are committed, the file shows up in the list of pending check-ins.
Have anyone else using the project select Home / Get Latest on the ribbon bar to receive the latest version of all CaseComplete and related document files.