I bought a Latitude XT Mediabase and the DVD/CD drive won't show up

I bought a Latitude XT Mediabase with RW DVD/CD on ebay. It did not say if it's exclusively only for XT1 or XT2, but it did say 'Latitude XT series'
Dell MultiMedia Base Docking Station Latitude XT Series Tablet PC KT666 PR12S | eBay

I think the model is PR12S KT666 or something like that.

I tested it with my Latitude XT1 (Intel core 2 1.33 ghz with ATi graphics). The USB ports and DVI display adapted worked... but not the RW DVD/CD drive. The RW DVD/CD drive is not even recognized at boot mode.

Did I just purchase a defective unit, or it's incompatible with XT1?

 

On my E6220 I have to go into the device manager and search for new hardware to get my CD/DVD drive to work.

The media bay uses the docking port that's just a combination of pins from different I/O ports. Your CD/DVD drive likely connects over an eSATA lane, but even with that considered it should still be recognized at boot as a bootable option.