The Mapping node has one or more mappings that are stored in message map files (with a .msgmap file extension). These files are configured using the Message Mapping editor.
If a message mapping is between elements of different types, you might need to include casts in your mapping definitions, depending on which runtime parser is specified by the Message Domain property of your message set.
The Mapping node uses a language to manipulate messages that are based on XPath.
To develop message mappings for a Mapping node, use the Message Mapping editor, which provides separate panes for working with sources, targets and expressions.