Well, if you are using a vest/brace, it really shouldn't be that hard. Make sure you aren't overloaded somehow..
Instead of arm exercises, I suggest dance. Learn how to balance and control all aspects of your body, and feel comfortable in that space, and you'll probably have a better time coordinating your movements with the stabiliizer as well.
But if you're definitely looking for arm exercise, do at least chest and mid-section also...Isolating any one area of the body is likely to cause strain and problems.
I mean, exercises specifically designed to improve my stabilizer skills - "exercises" in the sense of, put-the-stabilizer-on-and-do-exercises-with-the-camera-running-to-learn-to-use-it-better.
My wife is always trying to encourage me to dance. In spite of having seen what that looks like.
