@mtins:
Loki is great at getting in the crate when we're practicing, but when it comes time for us to actually crate him and leave for work, he's still having none of it.
Yes, because he knows you are leaving him locked in there! This is a hard one to fix, once they have "figured it out". I had a horse that hated trailering, although I had trained him to load into the trailer and in practice I could lead him to the ramp, throw the lead rope over his neck, and he would walk on and stand while I closed it up. But if he knew we were actually going somewhere, it would take a long time to get him on! He was genuinely afraid of the experience, and would paw and defecate, put one foot on the ramp, take it off, etc. until finally he would overcome his fear and walk on, but when we got where we were going, he was always drenched in sweat. I felt sorry for him, so we didn't trailer very often.
If Loki is actually afraid of being left confined, it makes it very difficult, because he will pick up the cues that you are actually leaving, as opposed to having a training session. The only advice I can offer is to vary your routine enough that he isn't really sure which it is, and that's hard to do when you have to meet a schedule. Clicker training is great for teaching him what you want, but it would seem he already knows.
There are lots of articles and youtube videos on the subject, but as I said, it would appear he already knows the basics. Training him to go in is not your problem, teaching him to like it when he knows he will be left alone is. I would suggest making his crate a very desirable place to be, by asking him to go in often when you are home, and rewarding intermittently. I would also tease him with something very delectable from time to time, and put it in his crate and lock him out, so he wants it. Build anticipation for the moment you open the door and allow him to get it. Don't only do this when you are going out (so he doesn't associate it only with you leaving), but I would do it when you are going to leave.