We are unable to configure remote cache store for a particular cache from RHQ GUI for a server.

It does not even put any configuration fragments into standalone.xml file. The only reasonable message I was able to extract was INFO from a RHQ server itself:

09:45:16,719 INFO [org.rhq.enterprise.server.resource.ResourceFactoryServerServiceImpl] (http-/0.0.0.0:7080-6) Received create resource response: CreateResourceResponse[RequestId=10111, Status=Failure]

Unfortunately, TRACE logging says nothing there.
ISPN server and Agent logs does not contain any useful information either.

This issue needs to be investigated further and deeply. This is just the first heads up and for a proper tracing of this bug.