When you export Midi from Strike, it creates MIDI tracks, and those MIDI track names contain the channel you need to assign them to. They normally start with channel 3 (MIDI Channels 1 and 2 are reserved for stereo outputs of Strike). So if, for example, an imported MIDI track is named "StrkKikC3" you should set that MIDI track's output to Strike1-3 (channel 3).