If you added levers, they're likely the inline interrupt levers. If the levers don't pull the barrel end of the cable (which should be in your drop levers), they won't work alone. They should expand the housing on either side of the lever, but still require the end of the cable to be connected to something, like a brake lever.

As AllenG mentioned, the trekking bar will be a different diameter than the drop bars you currently have, so your existing brake levers (inlines and drops) and stem most likely won't fit and you'd need something sized for "mountain bike" bars.

Personally, I'd prefer the moustache bars, but can't fit the obligatory grip shifter for my internal hub.