yes. you can find a cheap LED flashlight from HF, take the 3 battery pack holder out and solder servo leads to it (only need power and ground). 3 AAA batteries will give you the voltage you need, then just plug into empty spot on your Rx. i have done this on DLG's before and it works fine.
those will work but 4 batteries is a little over kill for voltage and weight. i really like the cheap LED flashlight that you can get for $1. they have the same thing but with 3 batteries instead of 4.