I have thought of this and will try it out but in my case it isn't a spell that requires an external target like something you can mouse over.
I'm using the trap launcher which gives a buff but while its up you have to select one of your traps which you then use the green target circle to place.
You may be right and, in that case or in the interim if I find out otherwise, I may just have to make 2 buttons for each.
If I could make it work similar to blizzard's action buttons and just have the 5 that change spell state when that buff is on that would be nice but I am thinking that's a special deal only blizzard gets to do.