MIDI drum to trigger keyboard sequence

You can possibly set something up under Preferences|keyboard shortcuts. In the shortcuts section, you can alternatively assign midi notes as shortcuts to do some sort of Sonar actions. I use the lowest couple of notes on my keyboard for start playback, stop playback, and pause. (I also have a whole live setup using a dedicated extra keyboard that sends all sorts of "special" midi messages, for a specialized music and computer-generated art gig thing I do.)
 
You might have to set up something where you hold down the hi-hat pedal (switched on, so to speak, sort of like holding down the control key on the computer) while you hit a specific pad to trigger the playback.
 
Alternatively, consider getting an el-cheapo mini keypad for triggering these actions.