Would you like to create a better description of the filter-system in the wiki?
http://wiki.phex.org http://wiki.phex.org/How_To_Contribute
We're always searching for people who'd like to contribute, and it would be great to have a description of the filters.
(inverse filtering is simply done by assigning no "case-condition", then assigning a consequence and the assigning an "except if" condition.)
On the other ones Gregor should be able to give better answers than me...