How can i get my iPad 3 to play music via the output (aux to my stereo) and bluetooth speaker at the same time?

How can I get my iPad 3 to play music via the output (aux to my stereo) and bluetooth speaker at the same time? I have a JBL bluetooth speaker (fabulous!) and would like to use it as an extra speaker when playing music in the house. So I have a cable from the output on the iPad going into the aux on the stereo and I have paired the iPad and JBL speaker. However, as soon as I plug in the output cable the bluetooth stream stops. I was positive the iPad could do both at the same time??? I also have an iPhone 5 which I haven't tried yet.

Thank you for your help!