It's not so much an issue with the healing, I can keep up with that fine, I was just wondering whether it's possible to do, because it might be useful to have.
But okay, here's my character: http://eu.battle.net/wow/en/character/silvermoon/Seranuia/simple
And normally I'd use Eternal Flame (assuming I have holy power charges up, which I normally do because of the Holy Radiance > Holy Shock proc rotation) and then Holy Shock. By this point if he's still not in the clear I'll throw a Flash of Light on him, but again it's not really a problem, and when it is, it's because it's LFR and people are clueless. Doesn't really happen in guild runs.