WHY!! Why can't we expand from 8 to 16? PowerEdge R820

Everything on these servers is modular! We got an R820 with 8 bays under the assumption it would be a quick upgrade to throw another 8 bays in there. Boy were we wrong. I have been on the phone with customer service, tech support, scouring the internet. Why is the HDD carrier for bay 2 not available to buy? It seems like every other part is easy to obtain. We can get the backplane, the cables, the raid controller, but not the hard drive carrier for bay 2? Is there anywhere to get this part? The blank just slides out like there is a bay 2 carrier in existence somewhere that would just slide in and take its place. Please let me know if you know where we can get this bay 2 hard drive carrier. 

Thanks!