Well, yes, Brian, that's one way but who is going to invest for a month in an ongoing beta which may or may not deliver? I want to see it working for myself before I invest. You really can't charge the punters for a beta anything.
I'll add that the way to go should be to introduce this option, as a beta, for say, a month, (or until it becomes a robust release candidate) with the proviso that a charge will be levied on those who wish to retain the feature once publicly released. But until it's stable (and the new version 3 is stable, for that matter), it's not really on to levy any charge at all.
DC