As indicated at the URL above, this device is not a compression tester. It's a CIS fuel system tester. Look at all of the attachments.
baumtools.com has a similar tool. I believe the part # is 8034-3.
You might try contacting them and see what the story is on all of the fittings.
Could be what you are looking for.
You might also want to look at the following:
http://www.peachparts.com/shopforum/showthread.php?t=73428&highlight=fuel+pressure+testing