I dont think touching them up will be the answer - they'll just keep peeling - for a permanent repair you'll need to take them to a specialist for professional refinishing. Thats what I'm planning to do to mine when I can be ar5ed.
Had this problem on my Fiat Coupe, it had titanium coloured alloys ( check the site for an idea of the colour ) that nobody could give me a paint code for, most annoying, anyway a trip to my local chipsaway ( www.chipsaway.co.uk ) solved it they took the wheel off and did a colour match by eye touched the wheel up, relaquered the wheel and it looked perfect, colour was identical to the rest, cost £40 to get the wheel done with the colour match but its cheaper without if you have a standard silver type alloy (£30) , they would also do a deal if you had the lot done.
I have had this problem with my V, tried touching it up but as 'dlgis' says its not a permanent fix, they will continue to flake no matter what you do. I will soon be getting mine bead blasted and repainted back to original, its the only real cure. Will loose the OZ logo though