How to support Finder preview pane for new application file types

[rhoge at nmr.mgh.harvard.edu (Rick Hoge)]

I've floated this question on a few forums and have yet to get any luck 
- have seen a similar query in the archives here (with no answer).  
Sorry if this is dumb:

I am working on a Cocoa document-based application, and would like to
be able to provide preview information for the Finder for the file
types supported in my app.  I have not been able to find any
documentation on how this is achieved or what the possibilities are.

Generally the Finder seems able to show a preview image, as well as
the text fields Name, Kind, Size, Created, and Modified.  How are
these fields generated?  Is it possible to provide custom fields for
new file types?

I remember something about this being handled by QuickTime, but I can't 
find this reference...

Thanks for any suggestions!