The following will illustrate how to update the self signed certificate on NSX Manager 6.2. I am using a Windows 2012 CA.

First we need to generate the request. Log on to the NSX manager and log in as Admin. go to Manage - SSL Certificate - Generate CSR

Enter the required details

Click OK to this and save the request to your machine. Browse to your CA http://servername/certsrv and login. Choose Request a certificate – advanced certificate request – submit a certificate request by using a base-64-encoded CMC or PKCS #file…. copy and paste the details out of the request previously created either using Notepad or Notepad ++

Click Sumit and save the as Base-64. Browse back to http://servername/certsrv and click Download CA certificate. Again select Base 64 and save to the local machine. from your local machine open a command prompt and browse the directory where these files are saved. Enter below - change the file names to match yours

copy certnew.cer+root.cer nsxmanager.cer

Go back to your NSX Manager - Manage - SSL Certificate - Import. Select the new .cer file

All being well it will import

Reboot the appliance.

Once rebooted you can browse to your NSX Manager with the correct certificate