Look at it this way.
I highly, highly doubt that he can hurt your business much – but you can certainly hurt his.
Send a letter to his host, telling them that they will be the subject of legal action if he is not forced to cease and desist publishing untrue information about you.
He might not care about a C&D – but his host certainly will.
In the meantime, you may want to say who VD752 is.
What’s worst about all this is that the thread about you is the ONLY thread on the forum with any participation – which leads me to believe most of his traffic comes from you and people bashing you!