yeah, I tried the z,x,c,v,b,n,m buttons and none of them seemed to work.

I think it's supposed to snap to the outer surface of the sphere.. but nothing I try is doing that.

I didn't try other buttons than the ones listed because I didn't want to mess anything up to bad..

So you guys don't use this constrain verts to surfaces?

If it's something not used normally then I won't worry about it and work around it.