solved! As it turns out, this is so frustrating only because there is an additional step needed: once the USB has been set to storage mode in the Android setup options and then the USB cable connected, a status message will appear to say the USB is now connected -- you must OPEN that message (doh!) and in that message there is a dialog to enable the USB as a storage device. Click 'mount' and there it is, a valid drive on the Ubuntu desktop! To un-mount, you must unmount the drive in Ubuntu and then click the unmount button to break the connection.
solved! As it turns out, this is so frustrating only because there is an additional step needed: once the USB has been set to storage mode in the Android setup options and then the USB cable connected, a status message will appear to say the USB is now connected -- you must OPEN that message (doh!) and in that message there is a dialog to enable the USB as a storage device. Click 'mount' and there it is, a valid drive on the Ubuntu desktop! To un-mount, you must unmount the drive in Ubuntu and then click the unmount button to break the connection.