I don't see why not, but that's just my opinion. Since the soulmeld grants natural attacks, it technically meets the prerequisite of the feat. Others may disagree on the basis that a soulmeld is like a permanent magic item, and they don't like the idea of using magic items to qualify for feats.
The real question is, will this re-open the whole "Can monks take Improved Natural Attack?" can of worms again?
Not that it has any basis in the ruling, but I would certainly allow it. It's not overpowered on its own and you can't use it when you don't qualify for it. Actually, it seems like a sub-optimal choice to me, so have at it IMC.