About editing the "alignment vector of a matching connection point

I have a hard time making two figures connect to each other the way I want
them. This is mainly because of the so called "alignment vector of a matching
connection point". As you all know, each connection point is assigned an
alignment vector, useful for repositioning of the shape when another shape is
attached (connected) to it, or for the proper direction of the connector when
"plugged" into the connection point of a shape. The coordinates of this
alignment vectors can be edited in the ShapeSheet in "DirX / A", "DirY / B"
cells under Connection Points section.
My question is what is the meaning of these coordinates, and what is the
easiest way (preferably visually) to edit the direction of this alignment
vector?
I remember reading something about this in the help files somewhere, but
cannot find it anymore.

Thanks