Pin Missing Exception

I’m using I’m using on a Cobra II WiFi with extender and want to use an XBee and Tunes module. The Cobra only has the one P socket (7, P,U,Y) but when I try connecting the XBee to socket 5 (U,X) I get ‘Gadgeteer.Socket.PinMissingException’ thrown.

Is this a bug with the SDK?