So, I just got a few of my soldiers in Enemy Within up to Colonel Rank, and another soldier up to Captain so I decided I was going to make them into MEC Troopers to balance out with my Psionics. However, it won't let me. When I go to select them for the augmenting process their names are grayed out. But I can modify their genes if I want to, though I haven't yet on either of them.
Some help would be greatly appreciated.