Ok i finally got it - took a deeper look with notepad++, compared genericon with font-awesome and found out that there are differences in "@font-face" - for some reason on half of the sources the values and not commands have been marked bold meaning:
src: url('../font/genericons-webfont.eot?#iefix') format('embedded-opentype'), url('../font/genericons-webfont.woff') format('woff'),
I couldn't find the real source for that - the code itself was ok, just ... i.d.k. Anyway i copied over the clean part from font awesome (, fixed the link,) and it's working now. Still if anyone got an idea how this could have been possible, i'd like to learn on.