Start documenting everything. Dates, times, places, exact quotes, circumstances. If you're going to file a harassment claim, you have to have a record to stand on. Don't do it in front of the HR person, otherwise he can claim that you're harassing him. Just make sure you have everything down on paper. When you're ready to make a formal complaint, give other people only copies...never the original.

A PIA, I know, but this is the only way I know of to make sure the harassment charge sticks.