A few million miles prior to arrival, jettison a 'probe from the probe', control this separately, beginning the negative acceleration of the mini-probe. This mini probe could enter a controlled orbit, and then launch a mini landing probe of even smaller size...etc.

Getting something to slow down enough to orbit is still a huge change in velocity. And even if it did, exactly how much bigger a transmitter could it carry considering it has to be hurled out to Pluto. At least with direct to Earth transmissions we can aim enormous[1] dishes at the signal source.

[1] http://deepspace.jpl.nasa.gov/about/DSNComplexes/70meter/

Putting something else in orbit is the hard part.

The relay doesn't have to be in orbit around Pluto, it could be trailing the impacter and fly by. Deep Impact did something like this with a comet.