I also erased all my var/ directory to see what's happened.. It was an error, I lost all my images...
I think there's another file to modify, but which one and where ???
I tested also, which is not recommended, to write into contentstructuremenu.ini in "settings/"
directory... i wrote the same code in the "ShowClasses[]" attributes. (like my first message)
When you have such problems first you must see what eZ sees. Go to Setup->Ini settings, choose contentstructuremenu.ini file and your admin siteaccess. Clicking on "Select" button you will get ini settings which are used.
If copy_of_frontpage is there then the problem is with some cache, if not you didn't set it right.
Greetz
ps. try to disable Dynamic value and see what happens
