Currently, Jive Cloud is not optimized for External Sites. You're correct that, the above-mentioned system properties are not available for Jive Admins on Jive Cloud.
Thank you Nick for the advice.
Some Jive user like us want to start small with Jive cloud and if it grows, then we hope to make them officially into public facing community.It would be wonderful if Jive can open some of the system properties to Jive cloud users.
Thank you for answer it clarified the question.