Questions about Casio WK-110 keyboard...?

I like to make beats on my Casio WK-110 keyboard and I was wondering if there was a way I could record 2 things and have them play over each other. I hit record twice so that I can record my synth or what ever, than when I try to record drums over it, it just records overwriting the synth, but I'd like them both to save then eventually play together. I've look through the manual and cant find anything.