german menu and UTF-8

Dear list-members,

since I changed my system to UTF-8 (I recompiled the whole system under 
Gentoo) my Fluxbox-Menu is something missing. - Some entries are broken after 
a german "umlaut". Other entries where the "umlauts" are rewriten (ä=ae, 
ü=ue) are OK.

Can someone explain me how I can rebuild my '
/usr/share/fluxbox/nls/de_DE/fluxbox.cat' that it works with UTF-8 (remember I 
will use a german menu and would translate some entries too)?

I attached my de_DE/fluxbox.cat for all people that wanna help me.

Thanks
sokai

PS:
The "umlauts" are working for iso-8859-1 and iso-8859-15...