It is possible, you'll need:
1) original 600ss RH fork leg with lugs
2) Master cylinder for twin disk bike
3) RH caliper
4) New brake lines
5) RH disc
Depends on who you source the parts from, but it could be anywhere from £200-£350.
I use a brembo radial master cyl on a single disk with a brembo billet caliper, and it's easily enough for road and racing, tricker than the standard setup, better feel, and cheaper. Drop me a line if you want a hand sourcing parts, or questions on setup.
Cheers,
Ali
07748 687348