Whether or not to require signed receipts.
When sending a file to a trading partner, set this to true if the file receipt should be signed by the server. When this receipt is received by the connector, it will be verified during processing.
NOTE: If the server does not attach the public certificate in the signed message, the server's public key must be specified in the RecipientCert property in order for verification to succeed.
This property is not available in the Receiver.