AudioDeviceManager and chaning input channels!

Hi

I using the AudioDeviceManager class and have initialized it to handle 4 input channels from the soundcard. With my Digidesign Mbox2 (pro) I have 6 physical inputs (2 stereo pairs of analog ins and one digital input channel) which are shown in the dialog box of the audiodevicemanger.

Now, I have tried to un-mark the analog stereo input channel 2 (in the middle of the list with the 3 input channels but it can’t be changed. I can only mark/un-mark the other 2 channels.

Can someone confirm that the audiodevicemanager has a flaw?

Best Regards
Thomas