External Instrument - Program Selector

I have the following question.

I have set up at External Instrument i Cubase (6.5.5).
I use my Yamaha CS1x - this syhtesizer is predefined i Cubase MIDI Device Manager.

I sendt midi signals from Cubase to CS1x og audio from the CS1x to Cubase.
This part works great.

My question is:

I chose the External Instrument CS1x as MIDI output on the Instrument Track which contains the midi data.
Then I chose a preset patch in the Program Selector.
When I change a preset here, the sound on the CS1x changes - but the patch names in Program Selector does not give me the sounds which are described in their names.

Example - if I choose Viola my CS1x gives me a square bass sound.

I have reset the CS1x to factory settings - but this does not change anything.

Can anyone help me out here?

Best regards,