Cerbuino Bee SDDetect

Does any one know how to implement a SDDetect routine on the onboard microSD on the Cerbuino Bee?

Add on: The Eject event seems not to be tricked by an Eject of the microSD.

Her it is:

InputPort sdDetect = new InputPort((Cpu.Pin)(0x22), false, Port.ResistorMode.PullUp);

bool Inserted = !sdDetect.Read();