Siebel provides good tools for working with Siebel Hierarchies, e.g. a developer can query Siebel data using the EAI Siebel Adapter business service, transform the queried data into an instance of external integration object using the EAI Data Transformation Engine business service, and then send the result to an external system. If there are no complicated requirements, and the transformations are straightforward, most of Siebel developers can implement outbound or inbound web service in a couple of hours.