This isn't supported directly. However you can use new functionality in VMRC 8.0 added to support vRealize Automation and launch an MKS-only session. It's easy if you have a recent version of ESX--at the command line:
- Get the MKS ticket for a VM given its MOID: vim-cmd vmsvc/acquireticket <moid> mks
- In addition to the ticket, ESX will create an almost-ready-to-use vmrc:// URL which also contains the SSL thumbprint. All you need to do is replace "localhost" with your actual host and send the URL to VMRC.
The general format of the URL is
vmrc://<server><:port>/?mksticket=<the MKS ticket>&thumbprint=<the thumbprint>&path=<the MKS verification path>