[Typo3] Replacing RTE editor with another

[Carsten Gehling]

I've bought a license to the InnovaStudio WYSIWYG editor (
http://www.innovastudio.com), which I think is a very powerful and
userfriendly HTML editor (still based, of course, on IE's editor component).
 I would like to use this editor instead of the RTE editor, that comes with
TYPO3. I've haven't looked at TYPO3's program code yet. First I wanted to
ask the good people here, if you have any experience in this area. How hard
is it to replace the RTE editor?
 - Carsten