MWN samples are available here. They cover the following aspects:
A round trip where a record company sends an MWL request to a publisher who replies with an MWL claim message;
A series of round trip via a hub to deal with a number of scenarios:
Provision of an additional publisher;
Provision of an additional writer;
Handling of unclaimed writers;
A complete and a partial claim;
A claim message showing how to communicate a collection share without a manuscript share;
A claim message showing how to communicate multiple original publisher shares;
A claim requests sent to from a record company to a hub who then forwards the request to two publishers; and
A set claim requests in one message sent to from a record company to a hub who then forwards the request to thee publishers.
All samples are being provided as a valid XML message and a human readable HTML file.