Yeah, I use a single XLR to the EP2500 with the DIP switch set to send it to both channels. However, I wasn't aware that it wouldn't have the same level to the signal. I thought it was a simple copy. mike c -- is that outlined in the manual that that will occur? (i.e., ch2 won't have the same level as ch1?).
mike c is also right that normal speaker wire will work. If you're talking about those different connectors, they're called Speakon, and you can order them from PE or whatever. However, I believe if you remove that little black plastic housing on the back, there are screw terminals or something (I never removed it -- I used the Speakons, but the Speakons are not necessary).
Good luck!