hey guys, to get the tremelo arm off remove the plate on the guitar back and look where the trem arm comes into the bridge. there is a small allen set screw (metric) that you can tighten or loosen to adjust the movement of the arm. take out the screw completely and the arm is free to be removed. hope that does it for you.
its a good thing you read this then, the dude at guitar center is deffinitly mis-informed to say the least. lol he's prolly never even been in the same room as an EB before that day.