Compare current to very old version

System

I am trying to compare the version of a file in the workarea to the content about 40 versions ago. The TeamSite UI (View->History in 5.5.2 WebDesk Pro) only shows me the latest 20 revisions, and while there is a "see next revisions" there is no "see all revisions" so I can't figure out how to select the current and old revisions for comparison. Selecting just the old revision and selecting Source Diff, it tells me that I must select two revisions. There has to be something obvious here that I'm missing. Other than hacking together a URL, iwrlog, checkout and offline compare, etc. what's the solution for comparing versions more than 20 submits apart through the UI?