If you are using modded/new objects in a DCG campaign then you need to tell DCG about them.
The three files you need to edit are armor.dcg, gobjects.dcg and gunits.dcg.
armor.dcg is meant for tanks only (originally DCG had a simple system - tanks capture locations and truck columns repair destroyed objects) but I notice in Slink's files he also added the infantry and armoured cars to allow them to capture territory. Find an entry similar to what you want to add and copy that one. The 05/08 values show you how this unit affects troop count at a location: +friendly/-enemy. It might be the other way around of course. :p
gobjects.dcg lists all the ground objects that DCG should 'care' about so it includes armor, vehicles, ships, artillery, trains, infantry and stationary objects. The numbers afterwards aren't very important. The first number is the side of the object and the rest can be 0. The text entry at the end tells DCG to use a different object if it can't find the new one.
gunits.dcg lists all the moving ground objects (armor, ships, trains, vehicles) that DCG will create routes for. So all your moving chiefs need to go in here.
Stock DCG usually works with tanks in columns of 3 or 4. If you want to use tank columns with large numbers then you will have to add them to all three files above.
If your 3rd party campaign does not include the three files above then DCG will fall back to the files in the \Data folder and any modded objects will probably not work correctly unless you've modded DCG's stock files.