I think the best suggestion is to just keep handling them, once they learn that they can back you down, they will.

You might also try the t-shirt trick. Take a t-shirt you've worn for a day and toss it in their cage, that way they'll (hopefully) get used to your smell and not percieve you as a threat. It's work for some people, and not worked for others.

Also, make sure their temps and humidy levels are where they should be. and look for anything that may be irritating them in their cages. Are they right next to the speaker of your stereo? anything causing vibrations that may be annoying them? Remember, they're much more sensitive than you are.