Should be a snap, depending on the diameter. I rarely use the drops on one of my road bikes (it's a little small, so the bars are too low), so I cut them off, then reversed the bars to make old-school "cowhorns" and mounted the levers backward, with the non-aero cables arcing out the front. Looked sort of like this, only with visible cables: http://www.all3sports.com/imageserve...ig/CNC200T.jpg
I might do that in your case rather than mounting to the bar ends. it's just one less joint to worry about.
You are talking about the bar-ends you have added to a flat or straight handlebar, aren't you? I would say the only thing preventing you from mounting your brake levers on them would be a difference in diameter. If the bar-ends are the same diameter as your handlebars you should have no problem. You will likely need new, longer cables.