So I finally got my Squier Stratocaster and the Midi controller for Rock Band 3's Pro Mode and wanted to try the training mode. But I got welcomed by the message:
You must use the instrument associated with this Trainer.
While the last training I did was with the keytar, I was now controlling with the midi controller. Logging in with a second account through the keytar didn't help either.
So how can I switch to the correct trainer or make sure Rock Band 3 recognizes the correct instrument?