iStudio - using the USB MIDI Out!

[GuyM]

How do you connect the USB Port out to a keyboard which has a USB MIDI Port too?

Is there is a cable which does this (USB Male B Block to USB Male B Block?)
OR
Does that mean I have to get a USB 2.0 to MIDI DINs cable and then add an adapter to convert the USB End to MALE B end to connect it up to the USB Port on the iStudio?

Anyone using a dock can you let me know please
Ta
Guy