1. If you put a zero price for PayPal button, you'll end with "Seller address is incorrect" error message, when you click on it. I think it would be much better, if a link to download would appear, if a price is zero (price="0").
2. requireRegistration option for particular button doesn't seem to work, no matter whether Require Registration turned on or off in component settings. Guess, it should.
All this stuff will be good for free downloads, which apparently shouldn't require any registration either.
