Problem loading units into transports

[purdune]

Howdy,
New to the game and liking it much. However I'm having a problem that must be me. Playing a friend in PBEM. I'm playing Germans in 1977. I'd like to buy transports for various units like the HQ which starts off as a 6 man unit. I have to buy a truck or APC seperatly. The problem I've noticed is the only way I can load units onto transports is if they are in the same platoon.

Example:

Headquarters is platoon A0. Buy a Fuchs and it's Platoon B0. You can't load the HeadQ into the Fuchs. You can't use the "Assign Current Unit to a New HQ" button as it tells you the Fuchs is a HQ. Grab a Marder, say K4, from a PzGrenadiers platoon K and use the ACUtaNHQ for the HeadQ. Now HeadQ is A0 and the Marder is now A1 from the previous designation of K4. Now you can load the HeadQ into the Marder.

So is there a way to reasign the "0" unit of a platoon to another platoon? Is there a way to buy transports and have them show up in the platoon they are for? Am I missing something dumb?