How to scroll a long form

I have a long web form (a survey for local charity) that I want to do all in Flash.

I can use HTML scroll bars, but SWFs are limited to a height of 2880 px so that’s insufficient.

So I am trying to use a ScrollPane - which results in a problem.

As a test, if I use a tall jpg, that scrolls okay. If I use a simple tall mc, that works okay, too. But when I use as the

scrollPane.source = mySprite

(which contains my form with nested checkboxes and textfields, etc), then the scrollPane doesn’t work. The top of the mySprite shows inside the scrollPane, but no scrollbars. If I force the appearance of scrollbars with

verticalScrollPolicy = ScrollPolicy.ON

then the scrollbars are grayed out.

Further, if I set mySprite.height = someHeight, then the mySprite does not show at all in the scrollPane. So that’s weird, and makes me suspect that ScrollPane class is buggy.

How do I get this to work? Thanks.