We're not licensed for the Integrated Remote Console, so we're using the Virtual Serial Port.
I think the definition of serial console from a HP VSP and the console of ESXi 5.1 differ.
From the HP VSP, you can get the logging from the ESXi server. [Quite an exhaustive logging] but you will not be able to issue commands from the VSP to the ESXi server. However, you can configure the HP system using the VSP.
For the console port in ESXi, I believe the above comments might suffice. Even on more requirement,
1. Press F2 in the yellow+black screen [DCUI]
2. Select Troubleshooting options.
3. Enable Local SSH and SSH options.
4. Open putty or any ssh client you wish to login to the server.
Or.
5. Open the Server by vSphere Client and select the Configuration>Security Profile>Properties.
6. Check SSH client and server.
You are good to go.