In regards to accessing the extsdcard from the PC connection, it cannot be done on the Android system. Android is set up to let a USB connection to PC mount the SDcard only, which in our case turns out to be the main storage. If you need to add files to your SD card you can a) copy to the main SD card and move after you dismount or b) send to your PE by means of something like Dropbox, Awesome Drop, SugarSync etc.