Luc,
having written a pretty complete validation plugin I could give you quite a lot of tips on how to build one. But I tend to think that it makes much more sense if you could just tell me what need from the plugin and I could tell you how you can achieve that with my plugin. And in case it isn't possible yet, I'm sure we can figure out a nice solution. I've nearly finished the first release candidate of the plugin, with some interesting new features (that were requested at some point) and some heavy refactoring that removed all depedencies on IDs in a form.
Let me know how we can get you going. -- Jörn Zaefferer http://bassistance.de
