You can access most of the normalized message properties from the BPEL Mapper. Certain properties, such as path and query parameters, need to be defined in the Source view.
Open the BPEL process you want to edit in the BPEL Designer.
In Design view, select the activity to add the normalized message property to.
In the BPEL Designer toolbar, click Mapper.
In the Output pane, expand the variable you want to edit, expand Properties, and then expand REST BC.
Expand Request Metadata or Response Metadata, depending on the message type.
A list of available normalized message properties appears.
Select the normalized message property you want to use, and use the mapper operands to build an expression or assign a value.
For a complete list of normalized message properties for the REST BC, see Normalized Message Properties for REST.