how can I delete presentations from the internal flash-device on the dmp4305G 5.0?
You will need to access the DMP manager software directly on the the DMP. Type in the IP address of DMP to get the user /pass. Utilizing the manager enable FTP and set to read and write. Utilize an FTP client to access the SAN disc on the DMP @ IPaddress/tmp/ftproot/usb_1. This info is in the user guide.
FYI...If you are pushing content to the SAN disc on the DMP with the DMD it will turn off the FTP function and disable read and write every time. Makes it frustrating some times.