Just keep reporting the posts and explain in details while reporting it. All his spam posts would be deleted and he may likely get temporary ban.
As a forum member then this is what I will also have to do in order to help the mods to clean up the spam posts since there's nothing else we can do but to report the post. I don't know if op is aware about the rules about forum members spamming in the forum because as far as I am concern is that op asked about this guy's spamming in the forum and ask for prevention although I really appreciate op's intention from the post and reason.