The shock sensor in the AGD will work but changes as your batteries weaken. You can wire two 9v's together in parallel for longer life and this will generally fix the issue.
The best solution for an Angel is the Interlink. Rob_AGD makes one in a kit. I bet he will sell a ton at ZAP IAO.
I have mine wired thru my intellifeed rail. Pics are on my teams site with a link to Rob's directions. www.stlgraffiti.com/mods.htm