Naturally you'll only be switching one leg of the 220 and using a 20 amp rated light switch should be of some concern. While it will work perfectly fine by only switching one leg of the 220V the unswitched line has 110V present at all times. If you forget this fact and go to work on the DC you'll be dealing with 110V.
A better solution might be to go to an electrical supply house not the BORG and see if they have the switch you really need. It is a Double Pole, Single Throw. When wired correctly it will remove all power form the DC.
Don Dando