iPhone 4s and JBL on time 200p

Im using my iPhone 4s in combination with a dockingstation/radio/soundsystem.

I use this at times to listen to my music, and i charge my iPhone daily on it.

Its works perfectly its a very nice system and with a good sound.

Since I upgraded to ios7 the combination isn't working anymore,

Now when i place my iPhone, a message apears: this accessory is not suitable for this iPhone.

And due to this message I can not play music on my JBL on time set anymore.

Luckily it still dos change my iPhone.

If I turn on music it now suddenly comes out of the iPhone and the speakers of the JBL set isn't working.

At times i use this set also as my alarm in the morning.

How can I solve this?

And get it to work?

It has been working perfectly for over a year, And now after the iOS 7 update it isn't working.

So my questions;

how do i set in iOS 7 what accessories i want to use?

Why can't I use my JBL set anymore?

How can I get it to work again?

I sincerely hope there is a solution for my problem.

Please help!