Generating TOC in nested sets

Hi,
I have nested structure of set->sets->books->parts->articles. To generate ToC I'm using parameter generate.toc with value 'set toc, book toc, part toc'.

What I want is to create toc for a root set. Right now all "child" sets have generated ToC, while my root set remains empty. Is there a way to generate TOC in main set?
Thanks,
Maciej