v26 plunge point lead in location...how to change?

right now my lead in is at a corner and i want it in the middle of a spline....i set my default chain start point in the middle. When i try and set my plunge point it say select start point on geometry. right click ok. I shift click my spline, select the middle point and it just seems to deselect that spline..nothing showing as selected. recomputing doesn't change lead in location....

ideas?help?

thx