I use needle nose pliers to put a light squeeze on the end caps. I haven't had a problem with them staying in place.

If I need to remove the cable for some reason, I'll squeeze the end cap at 90 degrees to the original crimp and gently pull it off. The cable end is typically undamaged and I rarely have difficulty re-threading it through housing, if I want too. Most of the time, I end up reusing the end caps.