Symptoms
Oracle service broker does not list the tables when registering the service instance.
Diagnoses
The Oracle service instance has to be configured with the correct accounts in the Owner list, so the tables could be seen under the schema.
Resolution
Following this document http://help.k2.com/onlinehelp/k2blackpearl/userguide/4.6.4/webframe.html_oracle_service_instance_configuration.html
both the K2 Service and the K2 Admin schema were configured in the Owner list of the instance. The tables were then displayed in the SmartObject tester for the users under the schema.