This looks remarkably similar to what's been commented on earlier, but symantec discovered it back in 2005
If it isn't the same, then it looks like something similar has been tried before. We use Symantec AV corp edition at work, and I wouldn't change from it. The submission system works very well, and the people you talk to work quickly to find resolutions.
As it happens, the last month or so has seen significantly reduced numbers of virus infected e-mails for us at work - out of around 40,000 e-mails in around 15 days on one of our servers, 130 have been virus infected, whilst around 8000 of them have been picked up as spam either by heuristic or RBL checks.