don't worry, i found a mod 
GeSHiSmf
that should do the trick
at least C and ASM are supported. don't know if freebasic is the same as basic, we'll see to that
I actually found it in the meantime, but it wasn't easy to install (version incompatibilities).
Test at will for now, and if all goes well, we'll keep it installed. To select the code language you now have a new drop-down selector in the posting page.
/* css code*/
.test {
color: #000000;
}
