setting up from new

Hi I have just bought a Tascam US122 MK11 with Cubase LE included, I can record guitar and playback no problem but when I record a Keyboard(Yamaha PSR E213/YPT210) I can only playback via Midi, so if I record a track with both guitar and keyboard I cannot hear both simultaneously ie the keyboard plays back only through itself and the guitar plays back via the Tascam to speakers.
Presumably I have not set up correctly?

Any help would be appreciated,

Cheers Dan

I think I understand what you are saying. A midi track requires a synthesizer or other sound device to have any sound.
The midi notes are instructions to the synthesizer to make the sound. You can record the midi track during its playback as a wave track and then not need the synthesizer for playback. You would eventually do that in the final stereo mix anyway.
hope this helps.