[TYPO3] Extending another extension's form - with a flexform

[Stephen Bungert]

I have made an extension that extends the tt_news extension. It creates two
extra fields on the relation tab of an article. While doing this, I thought
maybe I could create a flexform too as the article forms don't have one.

Is this possible? Can you create a flexfrom for an extensions form when it
doesn't have one? If yes, what happens if an extension creates a flexform,
and then you install another extension that also trys to add a flexform to
the same extension?

Would the first extensions flexform be deleted? Would two flexforms appear
on the form? Or would the sheets from both get merged somehow?

--
Stephen