I don't think much, if any, of the scent will come through.
Better off to save the vanilla beans for cooking.
Most often, infusing is used for colour, not scent. Though some report that some scent of various infusions make it through the soapmaking process, I've not had any success with that.
You'd be better off using a nice strong vanilla fo, there are lots, or benzoin essential oil is a vanilla type of scent.