Hello Flynn, What you are going to need to do is to go into the controller Bios of your H800 and you can then configure your MD1200 virtual disk.  Once you have the virtual disk created then you will be able to do a scan in ESX & it should see the virtual disk that are created.  To access the controller bios on boot you should have to hit Ctrl+C to enter into the bios.   Please let us know if you have any other questions.
Hello, I have purchased a Powervault md1200 and a perc h800 controller. I am going to install the perc controller in my PowerEdge r710 running esx 5.1. Then connect the md1200 to the r710 via sas cables. The powervault has no NICs. My question is, how do I configure the RAID when booting up the r710? I understand that if I was in Windows I could use open manage but I am unfamiliar with how to do it from an esx 5.1 server. I'd appreciate any assistance. Thank you, Flynn 
Connecting an Powervault MD1200 to a PowerEdge R710 running esx 5.1 using SAS 
cables