If you want to use bar end/bar con shifters on the trekking style bars, you would need to get a pair of Paul's Components Thumbies.
I have a Trek 520. Originally I did not want to use the drop bars that came w/the bike, so I installed a pair of Delta Ergo bars [ there's another bar choice for you ]. The Paul's Thumbies allowed me to turn me my 9 speed bar end/bar con shifters into 9 speed indexed or friction thumbshifters.
They come in 2 sizes one to fit on bars w/25.4mm clamp diameter, the other size fits on bars w/26.0mm clampo area [ I have a pair of each, I installed the 26.0mm thumbies on to the center section of my road bars, in case I want to try them there, haven't felt like doing it yet ].
Check it out, your lbs may need to special order them though.