I would think that it brings nothing to the party that you don't already have.
Not to mention they are touting this as a real-time scanner and that is clearly a no, no, to have two resident (real-time on-access) anti-viruses installed.
However this is about Immunet 3.0 (using the clamav engine, etc.) and not specifically ClamAV.
I have seen previous claims that Immunet is compatible and that has been proven to be inaccurate.