when ipod is in dock it will not stream music to bluetooth Speaker

I have an ipod touch bought DEC 2012 in a Brookstone Boombox dock made for ipad/ipod. Bought a Bluetooth Speaker. Paired it to the ipod touch and it plays fine, but when I put the ipod in the boombox dock, it plays thru the dock and stops playing through the Bluetooth Speaker. How can I get it to play through both devices simoultaneously?

Do I do this through Airplay?

Would it be better if I had a WiFi enabled Speaker rather than Bluetooth?