Colin,
Active Documents are NOT the way to go. The best approach to web based apps is to use one of the web frameworks like WebConnect, FoxWeb, or ActiveFox Pages. Use HTML forms and run fox code on the server to handle data.
Active documents are an interesting curiousity but nothing more than that. You are seeing that there is no easy way to connect to data in an active document. Your form can run nice in a web browser, but no data. Sort of useless.