Yeas i understand this is possible, i have an irig blueboard, but the computer must be connected for it to work this way.
it would be great to be able to use the blueboard, or another wireless able pedal to connect directly to the Xkey air 25 and allow it to sustain.
i have an Xkey air 25 and also a Xkey 37 with the break out sustain and midi cable, but this keeps disconnecting because the connection type is not very steady.
Perhaps you could consider a future software update to allow bluetooth connectivity to the Xkey Air 25 and 37 which allows wireless sustain pedal access. this would be really a game changer for many of us who want to travel light with minimum cables etc.