diff --git a/phase4-cef-client/src/main/java/com/helger/phase4/cef/Phase4CEFSender.java b/phase4-cef-client/src/main/java/com/helger/phase4/cef/Phase4CEFSender.java
index 48f2b981f..26afb7c67 100644
--- a/phase4-cef-client/src/main/java/com/helger/phase4/cef/Phase4CEFSender.java
+++ b/phase4-cef-client/src/main/java/com/helger/phase4/cef/Phase4CEFSender.java
@@ -383,6 +383,11 @@ public boolean isEveryRequiredFieldSet ()
         LOGGER.warn ("The field 'endpointDetailProvider' is not set");
         return false;
       }
+      if (m_aPayload == null)
+      {
+        LOGGER.warn ("The field 'payload' is not set");
+        return false;
+      }
       // m_aCertificateConsumer is optional
       // m_aAPEndointURLConsumer is optional
 
diff --git a/phase4-entsog-client/src/main/java/com/helger/phase4/entsog/Phase4ENTSOGSender.java b/phase4-entsog-client/src/main/java/com/helger/phase4/entsog/Phase4ENTSOGSender.java
index 48ad8b60b..0888b6488 100644
--- a/phase4-entsog-client/src/main/java/com/helger/phase4/entsog/Phase4ENTSOGSender.java
+++ b/phase4-entsog-client/src/main/java/com/helger/phase4/entsog/Phase4ENTSOGSender.java
@@ -175,6 +175,11 @@ public boolean isEveryRequiredFieldSet ()
         LOGGER.warn ("The field 'conversationID' must not be changed");
         return false;
       }
+      if (m_aPayload == null)
+      {
+        LOGGER.warn ("The field 'payload' is not set");
+        return false;
+      }
 
       // All valid
       return true;
diff --git a/phase4-eudamed-client/src/main/java/com/helger/phase4/eudamed/Phase4EudamedSender.java b/phase4-eudamed-client/src/main/java/com/helger/phase4/eudamed/Phase4EudamedSender.java
index ba7bfed48..d219c78d4 100644
--- a/phase4-eudamed-client/src/main/java/com/helger/phase4/eudamed/Phase4EudamedSender.java
+++ b/phase4-eudamed-client/src/main/java/com/helger/phase4/eudamed/Phase4EudamedSender.java
@@ -325,6 +325,11 @@ public boolean isEveryRequiredFieldSet ()
         LOGGER.warn ("The field 'endpointDetailProvider' is not set");
         return false;
       }
+      if (m_aPayload == null)
+      {
+        LOGGER.warn ("The field 'payload' is not set");
+        return false;
+      }
       // m_aCertificateConsumer is optional
       // m_aAPEndointURLConsumer is optional
 
diff --git a/phase4-lib/src/main/java/com/helger/phase4/sender/AS4Sender.java b/phase4-lib/src/main/java/com/helger/phase4/sender/AS4Sender.java
index 52be07f30..3d3c1f381 100644
--- a/phase4-lib/src/main/java/com/helger/phase4/sender/AS4Sender.java
+++ b/phase4-lib/src/main/java/com/helger/phase4/sender/AS4Sender.java
@@ -67,7 +67,7 @@ public static BuilderPullRequest builderPullRequest ()
   public static class BuilderUserMessage extends AbstractAS4UserMessageBuilderMIMEPayload <BuilderUserMessage>
   {
     /**
-     * Create a new builder, with the some fields already set as outlined in
+     * Create a new builder, with some fields already set as outlined in
      * {@link AbstractAS4UserMessageBuilderMIMEPayload#AbstractAS4UserMessageBuilderMIMEPayload()}
      */
     public BuilderUserMessage ()
diff --git a/phase4-lib/src/main/java/com/helger/phase4/sender/AbstractAS4UserMessageBuilderMIMEPayload.java b/phase4-lib/src/main/java/com/helger/phase4/sender/AbstractAS4UserMessageBuilderMIMEPayload.java
index b5e959504..da3ee6a36 100644
--- a/phase4-lib/src/main/java/com/helger/phase4/sender/AbstractAS4UserMessageBuilderMIMEPayload.java
+++ b/phase4-lib/src/main/java/com/helger/phase4/sender/AbstractAS4UserMessageBuilderMIMEPayload.java
@@ -51,10 +51,10 @@ public abstract class AbstractAS4UserMessageBuilderMIMEPayload <IMPLTYPE extends
 {
   private static final Logger LOGGER = LoggerFactory.getLogger (AbstractAS4UserMessageBuilderMIMEPayload.class);
 
-  private AS4OutgoingAttachment m_aPayload;
+  protected AS4OutgoingAttachment m_aPayload;
 
   /**
-   * Create a new builder, with the some fields already set as outlined in
+   * Create a new builder, with some fields already set as outlined in
    * {@link AbstractAS4UserMessageBuilder#AbstractAS4UserMessageBuilder()}
    */
   protected AbstractAS4UserMessageBuilderMIMEPayload ()
@@ -91,17 +91,7 @@ public final IMPLTYPE payload (@Nullable final AS4OutgoingAttachment aPayload)
   @OverridingMethodsMustInvokeSuper
   public boolean isEveryRequiredFieldSet ()
   {
-    if (!super.isEveryRequiredFieldSet ())
-      return false;
-
-    if (m_aPayload == null)
-    {
-      LOGGER.warn ("The field 'payload' is not set");
-      return false;
-    }
-
-    // All valid
-    return true;
+    return super.isEveryRequiredFieldSet();
   }
 
   /**
@@ -182,9 +172,11 @@ protected final void mainSendMessage () throws Phase4Exception
 
       // Add main attachment
       {
-        final WSS4JAttachment aMainAttachment = createMainAttachment (m_aPayload, aResHelper);
-        if (aMainAttachment != null)
-          aUserMsg.addAttachment (aMainAttachment);
+        if (m_aPayload != null) {
+          final WSS4JAttachment aMainAttachment = createMainAttachment (m_aPayload, aResHelper);
+          if (aMainAttachment != null)
+            aUserMsg.addAttachment (aMainAttachment);
+        }
       }
 
       // Add other attachments
diff --git a/phase4-peppol-client/src/main/java/com/helger/phase4/peppol/Phase4PeppolSender.java b/phase4-peppol-client/src/main/java/com/helger/phase4/peppol/Phase4PeppolSender.java
index 5acd8c462..9b8d9a159 100644
--- a/phase4-peppol-client/src/main/java/com/helger/phase4/peppol/Phase4PeppolSender.java
+++ b/phase4-peppol-client/src/main/java/com/helger/phase4/peppol/Phase4PeppolSender.java
@@ -845,6 +845,11 @@ public boolean isEveryRequiredFieldSet ()
         LOGGER.warn ("The field 'processID' is not set");
         return false;
       }
+      if (m_aPayload == null)
+      {
+        LOGGER.warn ("The field 'payload' is not set");
+        return false;
+      }
 
       // m_sCountryC1 may be null, before 1.1.2024
       if (PDTFactory.getCurrentLocalDateUTC ().compareTo (DATE_COUNTRY_C1_BECOMES_MANDATORY) >= 0)