After reading lots of code, I've found that it's impossible to do it gracefully, or I might have overlooked something, and please correct me if that is the case.

Now my next idea is to use my own checkout panes instead of the official ones. That would cause major redundancy, but it's a bit less of a problem than re-patching each release.

Damn, I wish someone comes up with a better idea cause my perfectionism doesn't like this workaround.

Tom

Thanks, that might be a better idea. My approach were to add a new text field, and that couldn't work because of the several hard-coded address field list, but adding a new line to the zone table on-the-fly with every submit might work. I will try it tomorrow. Thank you very much, will let you know the results.

Tom

Hmm... looks like that might be my bad. It appears you'll actually need to deal with the form values in the validate process. The problem is I'm not sure if you can safely manipulate the values in a validate handler. I guess it's worth a shot.