Thank you for your update! Unfortunately not all kind of types of fields works with special characters.
Single line textbox = works okay
Multiple line textbox = works okay
The rest have the same two bugs:
1) E.g. the letter ? becomes %F8
2) two words or more has a '+' inbetween like: "word1+word2" instead of "word1 word2"
So the bugs goes for: Multiple selection menu, Radio buttons, single selection menu and check boxes...
I hope that is an easy fix as these things didn't occur in the 2007 version. I doubled tested on a fresh install and with an established site.
Other than that your hack is for sure one of the most usefull. I have waited for an update for months....