The description for that extension point says, "internal... not provisional API", so I don't think you are going to find many examples. I can find no references. And I'm not sure how you "register custom components taglib.xml" - isn't adding the file to the project enough? What behaviour are you expecting to get?
It's possible that JSF 2.0 support just hasn't evolved enough yet to support your use case, but I can't say for sure since I don't know what that use case is.