[TYPO3] top content extension - how to ignore certain content types?

[James Knuckey]

I've found the top content extension to be very useful to add teasers of  
subpages to a main page. It's an easy way of making a summary with a  
minimum of fuss. It shows all content elements on all subpages, by pid in  
ascending order like told it to, with the first couple hundred characters  
of bodytext of each content element

The one thing I'm trying to figure out is how to make it not display - or  
ignore - content elements that have no bodytext, such as header content  
elements, plugins or images-only.

Can anyone give me any tips on how to do this?