custom options during save in a document app

[Riccardo Mottola]

Hi,

I want to handle two different filetypes during save in a document based 
application. For one of the type I need an option view in the panel to 
set some parameters.

I did that in a "standard" application. There it is easy: I have a save 
method which has the task to create and display the save panel, so it 
can instantiate it, add the view, read the parameters and perform the 
save by directly writing the file.

In my doc-based app however, I have a document and a window controller.
To save I have overidden "dataRepresentationOfType" (actual work) and 
"saveDocumentAs" (to add the file extension, nothing more).

dataRepresentationOfType is fine for now: currently type is "TIFF". 
Adding "JPEG" is trivial. I need however the compression rate, somehow 
an additional parameter.

But where/how can I add my view to the panel and handle its parameter? 
Can I override a method I do not see or do i need to throw-away part of 
what document-based apps offer me?

Riccardo