I'll have to dig, but if you can go to the Champions Online forums, you can find threads on programming aliases and binds which apply here.
There are likely the same instructions in any Champions Wiki.
Program a key bind that 1) targets yourself, then 2) triggers the hotbar slot your ability is in and assign it an easy to reach key. You can even assign it the number key that normally corrisponds to that ability, though you'll have to click it to use it on another when you need/want to.
I know it can be done here, I just forget the syntax. CO wikis and forums will have it.