Can I set Lightroom's white balance picker tool to choose a supposedly white/black spot instead of neutral grey?

Question

I'm correcting white balance issues in Adobe Lightroom 3. The white balance picker tool in the Develop module lets me to pick a light neutral grey spot in the picture from which Lightroom automatically calculates the needed data for white balance corrections.

Can I set the picker so I could choose a spot that should be white (or black) after white balance corrections?

Compare to e.g. Photoshop's curves and exposure tools which both have this feature (choosing either supposedly neutral grey, white or a black spot).

I do have access to Photoshop and could correct WB with it, but I'd like to edit the files non-destructively.

Answer 1

As per Nick's et al. answers in the similar photo.se question, mixed with own reasoning, the answer is:

You don't have to.

The white balance picker tool calibrates solely the white balance in the image, not e.g. the exposure. And if you look closely, the picker tool doesn't ask for target neutral grey but for just target neutral. One should pick a spot in the image where the channels should be approx. equal (R ≈ G ≈ B) after the automatic corrections — so it could be white, grey, black or anything in between.