Amavis-Postfix

Hello, I just installed with SuSE7.3 Amavis script for Virus filtering (+ Antivir). It is working apparently fine. The test with a dummy virus worked. Stupid question if somebody else works with Amavis/Antivir: I suppose the virus list must be updated. How to do it or is it done automatically via Web. The manuals are not very talkative and I am fed up of reading unexistent RTFM. Alain