Help ClamAV, Find Prior Art On Trend Micro Patent #5,623,600.

I was visiting Groklaw to read about last gasps of SCO, when I noticed the request for help to find prior art on TrendMicro Patent #5,623,600.
Rather than repeating, I will state the facts and guide you to the article. Thank you for helping and I will. The Groklaw post is pretty big, and need to read it to find out what really going on.
" We have another Pick Your Brain request. This one comes from Barracuda Networks, the email and web security appliances company, but it's about an attack on ClamAV, the Open Source antivirus product.

Barracuda includes ClamAV in some of its enterprise solutions, although it's a small part of what Barracuda does. And Trend Micro has accused ClamAV of infringing a patent it owns, #5,623,600. It specifically has named Barracuda Spam Firewall, the Barracuda Web Filter, and the Barracuda IM Firewall as infringing. Trend Micro has been trying to get Barracuda to either pay license royalties for including ClamAV or stop using ClamAV in its products."

Groklaw Article.

tag: Patent Busting, ClamAV, Barracuda Networks, Open Source antivirus, Barracuda Spam Firewall, Barracuda Web Filter, Barracuda IM Firewall, groklaw