If nothing else works, I guess you could also try yet another method: start painting the part in a durable white color, maybe adding a gloss coat for added strenght, followed by a thin coat of black with the airbrush (use a type of paint that doesn´t peel off in large chunks). Then, to reveal the white numerals for the final effect, simply sand down the phot-etched part very carefully against a flat surface. Use a very fine grit to ensure you only remove the black from the high points.
Hope it helps
That's almost identical to the method I suggested above, but you don't need to sand it off, you just wipe it off with your finger. Of course it only works if you have gloss white paint handy.
On another note, metal ID plates would be welcome for the Panda Paladin as well, as they are completely missing. To compound this the numbers are engraved, not raised, but I have a solution for this and may offer several number plates soon (with different numbers), along with other corrections the kit got wrong. Come to think of it, it's probably the worst release I've seen in the 21st century.