Black plastic beneath how to get over this?

Since the model is already black you are one step ahead of the game. Once you have painted it white and given it a clear coat, lightly sand the raised detail to expose it and you'll achieve what most modelers do when applying a wash on engraved detail.

Prime it with Testors silver enamel paint. It will be fine.

Just out of interest, what kit is it?

a heller spitfire xvi. they did not have at hannants uk premier store and found it at a local toy shop under 6 boxes of barbie dolls!!

Nice find!
Sometimes you can find the coolest stuff in the most unlikely places, eh?
Are you in the UK?

greece.....
by the way can you sent any japanese model store web adress?
i guess prices must be cheaper there for tami-hase etc. (do not know about mai cost ? taxes though)
ps2 have you ever heard of olympos airbrush? the store i checked presented it as the jewel of japan.....thanks