While it is not officially supported by Cisco, some customers need to change the default SSL certificate loaded on the VSOM server. This certificate is used when logging into VSOM from a browser over HTTPS (HTTP over SSL). In the spirit of full disclosure, the passphrase for the encrypted private key is stored on the VSOM server in clear-text, as you will see in this document. This means that anyone with root access to the operating system of the VSOM server can obtain this passphrase. Be sure to change the root password on your server and limit access to only those that need it. However, if you need your browser to trust the issuer of VSOM's SSL certificate, then this procedure should get you where you want to go.
Hopefully in a future release of VSM, we will have a fully supported and more secure SSL certificate implementation.