hmm i am not sure, that you can do that.
but an idea might be to create NTFS symlink
(Junction Point) to another folder, that should be transparent from the Virus side-of-view.
you can use this gui to create them:
http://schinagl.priv.at/nt/hardlinks...kshellext.html
or if you have windows vista, it can be done there too.
i have not tested it myself tho, its just an idea.
good luck