When you say did not detect it, is there no device created for the second drive?
Is it that when you put media in it is not recognized? ( if this is the case you can change to drive under advanced>configuration>devices> select the Disc Drive and scroll to the bottom of the page and change the block device to the proper location. ) I believe that it defaults to /dev/cdrom first, I have two drives. one is for network booting and the other is for media, I had to change the block device to /dev/dvd and it works like a charm.