iPad 3 will recognise my Zoom H4n as an external mic/interface

Hi, please help.
I have iPad3, Zoom H4n and a camera connection kit.
My objective is to connect the zoom to my ipad and record directly onto the ipad using the zoom h4n, I will be recording into "multi-track DAW" app.
But it is not working, I am powering the zoom with the mains charger and then run the USB from the zoom into the CCK and then into my ipad. I then turn on the zoom h4n and select "audio interface" and then "connect", so theoretically it should now work, but it doesn't. When I open the multi track daw app and start recording it is still using the ipad's internal mic and there are no options allowing me to change the input source. I know this can be done as i have watched loads of people on youtube doing exactly the thing that I am trying th acheive. I have sent these people messages asking for help but none of them have replied to me.
Please help.
Thanks
Dan