PPSSPP L2 and R2 buttons

By defaults, in ppsspp_libretto.DLL core - L2 and R2 buttons don’t exist. But i’m Tekken player and this buttons are very important to me. In PS3 this buttons are configured , like : L2 = cross + square, R2 = triangle + circle. Is it possible to configure (maybe emulate) this buttons in ppsspp core ? Any variants?