If you kill all eight of the IRHTs before you kill the last of the command trucks, you win gold. The trucks are guarded not only by German infantry and armor, but also by eight infrared searchlight halftracks (IRHTs), which supposedly use scanning IR beams to see through obstacles and detect approaching enemy units (i.e. The main goal is to destroy three well guarded command trucks.
The Espeler mission is a lengthy one requiring a specific sequence of movements around a large map, with more than a dozen firefights.
