As some people asked I try to show the setup I use for connecting the Polyend Play to the iPad :
First of all the Play is connected to a USB hub which is then connected to the iPad via the camera connection kit. This connection is used for the MIDI information. For the audio both devices are connected to a cheap audio splitter which actually serves as a „merger“ in this case (I was too lazy to use the real mixer).
I then configure the iPad to send MIDI clock and transport signal to the Play and tell the Play to listen for clock and transport on the USB. You can also do it the other way around, but this gave me some sync problems with Groovebox.
Apps used in this case : AudioBus and Groovebox
Hope this helps ☺️