How to play music over Bluetooth headset from iTouch 4G ?

I have a Samsung Bluetooth headset used for mobile phones.... I am able to pair it with my iPod Touch 4G and I am able to connect with it. My problem is that I dont know how to play music via that bluetooth headset ? whenever i try playing music via that i am unable to do so and the music starts to play via the speaker of the iTouch....

Can anyone help me with a step by step process for playing the music over the bluetooth headset ?