Designing the Service Contract - Oracle SOA Suite 11g R1 Developer's Guide - page 345

Ensure that Create Composite Service with SOAP Bindings is selected. Then click
on Find existing WSDLs (circled in the preceding screenshot) and select the WSDL
we want to import from the local filesystem. Ensure that the appropriate Port Type is
selected and click OK .
This will add an empty Mediator component to our composite and expose it as an
external service.
Note that if the WSDL references any external resources defined in the MDS, we
must first define the MDS repository to the applications; otherwise we will get an
exception when we try to create the Mediator.
The simplest way to achieve this, when we first create a new SOA application, is to
create the project using the template for an Empty Composite . We can then update
the adf:config.xml file, as described earlier. Finally, we can add a Mediator to the
composite and create it based on our predefined WSDL.
We can also create a BPEL process based on our abstract WSDL
by following the same approach.
Sharing XML Schemas in the Service Bus
As with composites, it is possible within the Service Bus to create multiple projects
each with their own local copy of the schema. However, as before, it's considered
best practice to only have a single copy of each schema.
This is easily achieved by having a single project that defines your schemas,
which is then shared across other projects. In order to be consistent with the SOA
infrastructure, we have defined the project mds , and under this, created an identical
folder structure into which we have imported our schemas.
For example, to mirror how we have deployed the order schema to MDS, we have
created the folder structure com/rubiconred/obay/xsd within the mds project, into
which we have imported the Order_v1_0.xsd schema.