No ToC in revision

Hi,
I'm using ToC in combination with Revisioning.
The strange thing is that the automatic ToC (setting is automatic in node type and in filter, setting in node itself is 'add to top' and correct input format applied to the body-text) is visible when I view the actual node (../node/%node) but not when I view an unpublished revision of that node (../node/%node/view(/%vid)).

According to the code of Revisioning both links have the same callback (node_page_view). Develing the code, I could find that the difference in body-text is appearing after '$text = module_invoke($filter->module, 'filter', 'process', $filter->delta, $format, $text, $cache_id)' in the filter-module. With a revision the ToC-filter doesn't seem to be applied.
Somewhere in the filter-hook of ToC something goes wrong, but I'm lost there.
Could you give me a clue?

Thanks,
Erik Greve.