Headset button pressed- How to get notification

Hello,

I'm developing a windows application.
My application involves bluetooth headset connected to the PC via bluetooth
dongle.
I'm using IVT BlueSoleil drivers.

My application requires receiving notification when a bluetooth headset
button is pressed.

How can I detect from my application, that the user pressed the button ? I
cannot find any documentation on that.

Thanks,
Nbd