hmm well this won't be posted for a while(since i'm still a noobie) but haveing other program languages the folling should work to make it go in the opposit angle(of course due to my new learning of db you'll have to figure out how to implement it into db also i well work off of say an x and y axis)
first:
ballspeed = 10
ballangle = 5
if (collision with say left y wall)
ballangle = ballangle - (ballangle * 2)
endif
that should reverse the balls angle exactly
now apply it to the z value and all other collisions
my smiles love me =-)=-)=-)(-=(-=(-=