I'm pretty sure, if the staff member witnessed you being racist to him, he doesn't need to provide proof for punishing you. Just because it's being brought up in a ban appeal doesn't mean he needs to provide proof, because that would go against the fact that if a staff member sees wrong-doing, he's going to punish the perpetrator.

Of course, any DarkRP staff- feel free to correct me, I just think it's way out of hand if the staff member suddenly needs to provide evidence even though he saw it first hand, and punished them himself.