It is possible to describe test cases with some values that come directly from the message payload (either input or output), for example EDI Customer Name of SAP Purchase Order Number.
To do this automatically from the Test Case Creator for PI/PO you need to provide the variable name that will store this value (in this case variable name is SOTEST).
Variable has to be created in the Automation Object for specific interface with the relevant rule to store value either from input or output message, as in the example below:
