[Mischback]

Ahh, missed the scoping...

	local PostUpdateHealth = function(unit, min, max)
-- set health background color
		local color = RAID_CLASS_COLORS[select(2,  UnitClass(unit))]	
		if (UnitIsPlayer(unit) and color) then
			self.Health:SetBackdropColor(color.r, color.g, color.b, .5)
		else
			local r, g, b = UnitSelectionColor(unit)
			self.Health:SetBackdropColor(r, g, b, .5)	
		end
	end

Still untested