Tried installing vCAC 6.0 on vSphere 5.5 (on ML110 - 1P2C, 8GB with SSD) but failed. However, when I retry on vSphere 5.1, it works. Services seems to start. When setting up vCAC ID appliance, make sure you use <<hostname>>:7444 when first registering the SSO portion. Some reason it does not change after the first time setup. You will need to simply redeploy the vCAC ID appliance and it works.
This is meant for educational purpose.