Copy HTML from textarea to editor in popup ..

... and back again on "submit".

I'm sure this has been covered before, but I just can't seem to find other than fragments for the answer to this, being the all-but-savy javascript ignorant I am.

I do not wish FCK to interact with my database, so what I have is a basic textarea with my HTML - but next to this I'd like to provide a link/button with the caption "Edit this in a Rich Text Editor".
When I click this link/button, FCK should pop up in a new browser window, with the HTML from the basic textarea in it.
And then again; when I click the submit button in FCK, the edited HTML should be pasted back into my basic textarea field in the parent window - and the FCK browser window closes.

I would really a specific example of how I could achieve that.

Thanks in advance, and thanks for a really nice and free editor!

PS. I'm running FCK with ASP - but that shouldn't really matter, since this is a client side javascript task only, right?