What I do is very low tech.
Insert the vehicles in the editor, set their rank so the leader is the highest, the next vehicle is next in rank etc. Then group the vehicles to the leader one at a time in the order front to back. Set their first waypoint to Formation = column.
I have only ever experience one problem with doing this and that is I had a hospital BRDM that kept insisting it wanted to be at the front of a support convoy not the back. I guess it thinks it is the fromation leader.
All my other vehicle convoys have worked well doing it this way.
Just try it and see.