youve got 2 options really... you can either stick the dials over the old black ones.. they will light up ok. you can do this without removing the needle as the hole in the middle of the dial is big enough to get over without having to remove the needle
OR you could if you can be arsed cut the old black dial away using a knife, the only problem doing this is they are PROPERLY stuck on and trying to remove the glue stuff underneath can be a nightmare.
CheeRs
Phil