adapting the link pop-up window

Hi-

I have adapted the link pop-up window, have added another tab-in the hopes of eventually adding ajax functionality to get a list of documents from a CMS server for display in the pop-up on the new tab I have added, to be selected by a user.

Long story short, I have to pass a variable to the ajax function to tell it what to query, but, am at a bit of a loss as to the best way to pass it to the pop-up. The parent window of the pop-up (which I thought was simply the main page that FCKEditor is displayed on) appears to be something other than that. So...am having difficulty wrapping my head around the best way to pass the link pop-up that information. I am using the Java integration pack, so I'm using the FCKEditor tag in a JSP.

Has anyone done something similar with any of the pop-ups in the editor?

Tobi