OK, here is the paper:
http://uclasod.dent.ucla.edu/CMS200S...20-%20Pang.doc
I re-read it and it certainly is not definative. It actually raises more questions than it answers. But it looks like alcohol at 4% concentration increases the abilty of HIV to infect epithelial cells (the cells inside your mouth). The mechanism is unknown, since epithelial cells do not contain the CD-4 protien, which is the method to infect T cells.
I have no idea of mouthwash concentration, but certainly food for thought.