ADDITIONAL INFORMATION:
For example, SystemManagerRootCA.
<Openfire install dir>\resources\security > <Openfire install dir>\jre\bin\keytool.exe -import -alias SystemManagerRootCA -keystore truststore -file SystemManagerCA.cacert.pem
Enter keystore password: <enter the Openfire Keystore password> (Default is changeit)
...
Trust this certificate? [no]: yes
Certificate was added to keystore