How do you turn on SNAP when modifying tuning?

Sorry if this seems like a silly question, but how do we turn on SNAPPING when modifying piano tuning? I made the mistake of moving the tuning in one of my projects, and it hasn't sounded quite right ever since.

Another problem is that I need to transpose the piano down by 1 step. For whatever reason, Sonar's transpose tools work on playback, but not during live recording, pushing the burden of the transposition onto the instrument.

How do I snap-transpose within the Akoustik Piano GUI? I don't even mind entering digits if that's required. But clumsily turning the tuning knob until the song sounds "kinda" one step down isn't precise enough for my purposes.

Thanks!