OK, good to know. I managed to get what I think is the source code for vsfilter. I think I'm bound to this particular DLL for my functionality because easySUP solves a lot of my other problems, and I'm trying to make a simple(ish) solution for the masses and easySUP gets me 98% of the way there...
I'll see what I can do. The code looks ... not simple ;) Hopefully the forums may yield something.