Tom it's not a bad question nor an uncommon problem.
But part of the problem with using a gennaker furler would be to get the rig out away from the pulpit. That is quite doable with a sprit, not sure it'd work well without that. Interestingly enough an inexpensive sprit can be obtained from catalina direct.
http://www.catalinadirect.com/index.cfm/product/2593/cruising-spinnaker-retractable-bowsprit-kit.cfm
perhaps a setup like this for a proper gennaker.
http://www.harken.com/productdetail.aspx?id=5713&taxid=537
Boy I'd love to see it setup if you wind up doing it, and I'd love to see the Capri 22 turned into an Asym monster. It'd turn the boat into a screamer off wind.
If that is too much extra cost (been there), and you plan on utilizing the existing symmetrical spinnaker, there are some easy ways of using it solo. You could pick a light wind day, launch from the companionway, under the genoa, and out. This allows you to blanket the spin as it goes up... AS far as dousing, again if you use the companionway, blow the halyard first while pulling in the sheet, make sure the genoa is out so it dumps easier (not under load). Believe it or not solo symmetrical spin launches on the 22 are pretty doable. I've done this a few times, but always in light air, I can't imagine attempting it solo under a lot of load...