I can't access the DAZ link right now (can't remember my password, and I'm at work), so I have no idea if this is already mentioned, but this is really the best way -- you can take the distance mask and adjust it in Photoshop so that the object you want focused is white and the rest is gray and black. Just use the Curves feature on the DOF alpha channel, click on the area where you want the focus, note where the circle shows up on the Curves line, put a marker where the circle was, and bring the top part of the line down -- making your marker the "highlight" of the Curves line. What this does is make your area of focus the whitest part of the alpha mask, and if you want, you can even further adjust it from there. Uh. This probably makes no sense, so I'll post some images...