Snap with spline command??

[WJWHILTON]

I can use object snaps when I am drawing a spline but when I want to pick <start tangent> or <end tangent> they quit working, am I missing something or is there some type of lisp routine I can use?? I know you can type the x,y,z coordinates but that's not always accurate if what you are typing does not exactly match what the x,y,z truly is (example: true point 2.56789,5.11259,8.11879 ; inquiry of point 2.5679,5.1126,8.1188).