Hi Jefal,
You can use SoundTouch presets for Spotify playlists, I will explain how you can do this.
To set a Spotify Playlist to one of your six presst buttons, use the following steps:
1. Open the Spotify app on a computer or mobile device
2. Play the desired Spotify playlist or genre & mood station through a SoundTouch system.
3. Open the SoundTouch app. The Spotify content that is playing shows in the Now Playing view
4. From the Now Playing view, press and hold the desired preset number to store the Spotify content to that preset number.
I hope this helps with your Spotify setup.
Thanks,
Shawn