Webhelp ToC tree depth

Hi,
First off, the WebHelp output is beautiful. Thanks to everyone involved!

Newbie question: Is there a way to control the depth of webhelp's ToC tree?
I'd like it to stop at 3 section levels deep, but the toc.section.depth
parameter doesn't appear to control this. I think I'm looking for something
equivalent to the htmlhelp.hhc.section.depth parameter that's available in
the htmlhelp output for controlling the depth of a CHM's ToC.

Thanks,
Mark