MIKMIDI soundfont preset selection

Question

I have successfully done the following in Swift:

• created an MIKMIDI sequencer
• added a track to the sequencer
• loaded a soundfont to that tracks's built-in synthesizer
• added MIDI events to the track
• triggered playback on the sequencer

Is is possible to select a preset in a multi-timbral sound font? Inspection of the availableInstruments property of the MIKMIDISynthesizer instance referenced by the sequencer track reports an empty array to the log console. Here's the code:

let _ = try sequence.addTrack()
let track = sequence.tracks[0]
let trackSynth = sequencer.builtinSynthesizerForTrack(track)

if let soundfont = NSBundle.mainBundle().URLForResource("fluid_gm", withExtension: "sf2") {
    do {
        try  trackSynth?.loadSoundfontFromFileAtURL(soundfont)
          print(trackSynth!.availableInstruments)
        } catch {

        }
    }


   let note1 = MIKMIDINoteEvent(timeStamp:0.0,note:60,velocity:100,duration:5,channel:0)
   let note2 = MIKMIDINoteEvent(timeStamp:0.0,note:63,velocity:100,duration:5,channel:0)
   let note3 = MIKMIDINoteEvent(timeStamp:1.0,note:60,velocity:0,duration:5,channel:0)
   let note4 = MIKMIDINoteEvent(timeStamp:1.0,note:63,velocity:0,duration:5,channel:0)
   track.addEvents([note1!,note2!,note3!,note4!])
   sequencer.sequence = sequence
   sequencer.startPlayback()