Nero Sound Editor: "Censoring" lyrics

I’m trying to use Nero Sound Editor 2 (included in Nero 6) to censor out some words in existing mp3 files.
I tried choosing a section and using the “Karaoke filter”, but a bit of vocal sounds are left.

What is the best way to do what I want to do?
Do any of the other tools/effects do that?
Or if I mess with the knobs on the Karaoke filter, will it do that? I don’t know what “vocal pan” etc. mean so I will appreciate any help.