2801572 - Messages failing in AS2 adapter with errors related to methods iaik.security.smime.JMailSMimeSigned or iaik.security.smime.SignedContent

You are using the AS2 adapter in your system from the Business-to-business Add-on 2.0. Your partner signs the messages that are sent to you or you would like to sign messages sent to your partner. The messages are failing with the following error in your AS2 adapter:

Catching java.io.IOException: Cannot write this object. It has to be an instance of iaik.security.smime.JMailSMimeSigned or iaik.security.smime.SignedContent!
at iaik.security.smime.signed_content.writeTo(Unknown Source)
at javax.activation.ObjectDataContentHandler.writeTo(DataHandler.java:889)
at javax.activation.DataHandler.writeTo(DataHandler.java:317)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1652)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:961)
at org.bouncycastle.mail.smime.SMIMEEnvelopedGenerator$ContentEncryptor.write(SMIMEEnvelopedGenerator.java:230)
at org.bouncycastle.mail.smime.handlers.PKCS7ContentHandler.writeTo(PKCS7ContentHandler.java:100)
at javax.activation.ObjectDataContentHandler.writeTo(DataHandler.java:889)
at javax.activation.DataHandler.writeTo(DataHandler.java:317)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1652)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:961)
at com.sap.aii.adapter.as2.ra.api.util.BouncyCastleUtils.compressSignAndEncrypt(BouncyCastleUtils.java:436)
at com.sap.aii.adapter.as2.ra.api.util.BouncyCastleUtils.compressSignAndEncryptAS2Message(BouncyCastleUtils.java:237)
at com.sap.aii.adapter.as2.ra.api.Deliverer.getMessage(Deliverer.java:577)
at com.sap.aii.adapter.as2.ra.api.Deliverer.deliver(Deliverer.java:120)
at com.sap.aii.adapter.as2.ra.jca.CCIInteraction.send(CCIInteraction.java:780)
at com.sap.aii.adapter.as2.ra.jca.CCIInteraction.execute(CCIInteraction.java:661)

• SAP enhancement package 1 for SAP NetWeaver 7.3 >= SP18
• SAP NetWeaver 7.4 >= SP15
• SAP NetWeaver 7.5
• SAP Process Integration 2.0, business-to-business add-on 

Process Integration 7.31, PI 7.31, Process Orchestration 7.4, PI 7.4, PO 7.4, Process Orchestration 7.5, PI 7.5, PO 7.5, XI, AEX, B2B Add-on, B2B Add-on 2.0, Business-to-business Add-on, Business-to-business Add-on 2.0, IAIK, BC, BouncyCastle, Security Provider, iaik.security.smime.JMailSMimeSigned, iaik.security.smime.SignedContent , KBA , BC-XI-CON-B2B-AS2 , Applicability Statement Protocol Adapter , Problem