There is a mod out (in these forums somewhere) that allows you to craft with a Water Bottle + Arrowhead.
Tbh, I believe the recipe is bugged from the Water Res Pot + Arrowhead recipe, because the two ways to craft Steam Arrows both create separate stacks that can't be merged.
I've still got Jahan in my party, so it's not really that big a deal. Still, having some water arrows on my Wayfairer would be pretty handy. Ah well, perhaps they'll patch it in at some point. Thanks everybody