iphone 5 compatibility with sony dock

I bought an iphone 5 and a lightning connector. When I plug both in my sony dock the iphone gets charge.

The problem happens when I try to play some music. Pushing play on my dock nothing happens, pushing play on iphone the music starts on the phone but stops right after and the volume bar disapears (like is with the other iphone that I have, the volume disapears since the music is played through the dock speakers and not through the Iphone). But nothing happens and the music is paused.

From that moment on, the volume appears and disapears until I take the Iphone of the plug or turn off the music application.

I read that the lightning connector would work to connect a 30 pin to the new plug of iphone, but I understood that it was not only for charging.

Can you help me making my Iphone 5 and connector compatible with my sony dock.

Thanks