Validate form with arbitrary number of dynamic fields

[DonDebonair]

I'm not sure if this is the same issue as #62, but what I'm looking for, is a way to validate a form in which the user can add additional fields/sub-forms by clicking a button. Imagine (for example) a user profile form in which the user can add extra contact address forms by clicking a button.

How would I validate these sub-forms when submitting the parent-form?

[jurassix]

If you can create a simple sandbox I'll help workout the pattern.