How large is your veiled? If it's still fairly young, such a large cage will make it almost impossible for him to hunt. If you try a smaller cage for a smaller veiled as a growing cage, he'll have no trouble at all. A 2'x4' cage is WAY too big for the 3" babies that I had at one point, while it is perfect for an adult. I actually started with a ten gallon cage for each baby, and then increased the size as needed.
It's annoying in a way that you have to have so many different cage sizes for your critters (well, many of them at least - most of mine go through 2-4 different sizes just to make sure they have everything they need but NOT too much space). But it's needed so as they can hunt properly, hide properly, and regulate their temperatures properly. There are some ways to get around the too-big issue with many species, but it's quite often risky if you don't know the species well.
Good luck with him. If he's in a properly sized cage for his size, give him 4 days or so for a baby or 2-3 weeks for an adult so he can settle. Give him peace and quiet, and try to not let him see you very much outside of what is absolutely needed. Then you can increase your time around him once he's settled.