Im not sure why you would want to shoot in Av mode... If your advanced enough to be processing HDR photos, you should be advanced enough to shoot in Manual so you have total control... Just my .02
true, i shoot in Manual too. however, its easier for beginners in HDR to go with Av first as I was responding to a photo with different aperture values.
This is a sharing thread, there are lots of other threads where you can discuss why manual is the only mode used by real photographers and how everyone else is a wuss!