I'm not sure what the exact question is, so here are some interpretations:
Do you want to know if vCloud Director 1.5 supports SQL 2012? No, that's not tested/supported. Clustered databases have not specifically been tested for all aspects, if you happen to use a supported version with vCloud Director.
Does vCloud Director care what database vCenter is backed by? No, it doesn't matter since we use the vCenter APIs to perform actions required ... therefore, it's database agnostic.
Does vCenter Server 5.0 support being being connected to MS SQL 2012? No, you need to be at least on vCenter 5.1 Update 1 to have support for MS SQL 2012.
I know that might not help, but will level set. MS SQL 2012 is pretty new in the grand scheme of things, so only the newest versions should support it.