SoundFont instrument selection in 4?

Firstly yes, I know that 4 is only about 2% complete, but I like what I'm seeing.

I'm just curious: how do you (or how is it planned that you will be able to) select what soundfont sound an instrument will playback with? That is, the "Sound: [Grand Piano v]" option in the mixer from version 3. I can see where in the mixer you can select which soundfont to use, but not what instrument to select from that soundfont.

I completely understand if it's not implemented yet, but I'm curious where, in that case, it is planned to be implemented so I can keep a lookout for it in future commits...?