[Gryphin]

Practical Answer:
The closest we currently can come to that is, (I think SJ or Geo suggested),
Create Heavily Armored / Shielded troops
Load them onto the transport first
Creat Heavily Armed troops
Load them onto the Transport Second

"Real Explanation"
Based on "hear say" that I could never confirm:
A trined bulldoazer driver with a large enough blade in soil with no boulders
could push up a "Wall of Dirt" 10 yards wide sufficient to use as cover for infantry in in 2 to 4 minutes. That of course is if no one is shooting at him.

Using 1/285 miniatures and 30 second turns, there never seemed enough time to prepare that kind of defence in a "Meeting Engagement".