PeopleSoft Common Question:

PeopleTools adds the PSCAMA record to every level of the message structure during processing. It isnt accessible in the message definition, but you can reference it as part of the Message object in the sending and receiving PeopleCode, and you can see it in the Integration Broker Monitor. PeopleCode processes this record the same way as any other record.
PSCAMA contains fields that are common to all messages. The <PSCAMA> tag repeats for each row in each level of the transaction section of the message. The sender can set PSCAMA fields to provide basic information about the message; for example, to indicate the message language or the type of transaction a row represents. When receiving a message, your PeopleCode should inspect the PSCAMA records for this information and respond accordingly.