I don't have the pegs you have, but I know the problem you are talking about. I believe you need spring clips, may be able to find some to fit at a local auto parts store... take a peg with you.. they look like the old style clips in a car breather that holds the crankcase filter in, I believe they come in different sizes.
I got my pegs from WWW. Parts-with-attitude and the hardware was included,and the spring clips for the rear pegs looked identical to the breather clips... just a smaller size... they work great... holds the peg up..
Hope it helps.. the clips are back, u-shaped and bow in the middle... tell them I sent you... that way they will think I'm crazy and not you. LOL! J.K!