Charger cable vs Lighting to USB Camera Adapter
I use an apple camera connection kit adaptor to connect my iPad to both my RolandRD800 &amp; Kurzweil Forte keyboards. My iPad runs the Unrealbook app which contains all my set lists &amp; songs, and behind each song PDF is a midi HEX string which is sent to both keyboards automatically when I select a song, and this midi HEX string selects the correct patches on each keyboard I require to play the song. 

Here is exactly how I set up my connections:


My iPad has the iPad camera connection adaptor plugged directly into it
Plugged into the other end of the iPad camera connection adaptor is a mini-USB 4 port HUB
Into the mini-USB hub I blug two standard printer cables (usb type 'a' to usb type 'b')
Then I plug the other ends 'usb type b' into the keyboards computer ports (one into the Roland and one into the Kurzweil)


There you go. All good. Works a treat. You should now be connected.

NOTE: Your iPad will not charge from your Roland. There is no voltage at the Roland computer port connection to provide a charge. Also the iPad camera connection adaptor is not configured to provide charge to your iPad. It is made purely to connect to a camera and transfer photos.