Unfortunately, Donner foot pedals are NOT officially supported by OnSong. They may or may not work/be configured within OnSong, but since they are not officially supported by OnSong, we have no means to test or troubleshoot with them, and we cannot guarantee that they will produce the desired effect in OnSong.
For a time, Donner listed us on their website and on their packaging as being compatible with their foot pedals. However, this was done without OnSong's knowledge or involvement, and we worked with Donner to have OnSong taken off of their website and packaging. Regarding this, any questions over Donner compatibility with OnSong should be directed towards Donner's support platform.