Klez virus bypasses attachment rejection script?

Hi everyone, I have set up the no attachments portion of the anti junk/html/attachment script available in the FAQ. It worked perfectly in our test list.... I then repeated exactly the same setup in our three largest lists which are suffering really badly with the level of infection with the Klez virus hoping that blocking the attachments would stop messages getting through. What I dont understand is how today a load of infected messages have got posted with their attachments in those three lists. Has anyone else seen this happen while using the script? Has anyone any bright ideas on how on earth we can protect our lists from this virus? for us its destroying many years of hard work. regards David