can't boot to external dvd player

I have a powered hub that I have attached a DVD writer/reader to. The hub is also connected to my Dell Venue Pro 8 5830. I can use this DVD writer/reader while in Windows 8.1 to burn a Macrium Rescue Disk. I've also been able to play videos with the DVD writer/reader while connected to my Dell tablet.

I want to be able to boot into the DVD player if I ever need to use my Macrium Rescue Disk to restore a saved backup image.

When I go into the bios to make sure that the DVD player is selected first, it is not shown in the list.

How do I set the Dell tablet to boot into the DVD player if it isn't shown in the Bios boot up list?