You must create a message definition file before
you can create the message model objects. The message definition file contains
the logical and physical model definitions of the objects in XML schema form.
To
create an empty message definition file from scratch:
The new empty message definition file, with the
name that you have specified and a file extension of *.mxsd,
opens in the Message Definition editor; you can use the editor to create your
own message definitions. If you have chosen to use a target namespace, a directory
structure that is based on the URI that you have supplied is created. The
new message definition file is placed within this directory structure, which
appears in the Broker Development view, the Outline view, and
the Overview editor.