diff --git a/33128/r18/TS33128Payloads.asn b/33128/r18/TS33128Payloads.asn
index ec9424938a38839e280f077e0ba2f1182c385175..9c2f70c92d5947bddd39b990af449b532b705ab5 100644
--- a/33128/r18/TS33128Payloads.asn
+++ b/33128/r18/TS33128Payloads.asn
@@ -7063,4 +7063,23 @@ MIMEBody ::= CHOICE
     bodyPart [2] MIMEPartIdentifier
 }
 
+-- =======================================================
+-- Externally Defined Structures - External ASN Parameters
+-- =======================================================
+ExternalASNType ::= SEQUENCE
+{
+    moduleIdentifier [1] OBJECT IDENTIFIER,
+    aSNReference     [2] ExternalASNReference OPTIONAL,
+    encodedASNValue  [3] ExternalASNValue
+}
+
+ExternalASNReference ::= UTF8String
+
+ExternalASNValue ::= CHOICE 
+{
+    bER          [1] OCTET STRING,
+    alignedPER   [2] OCTET STRING
+}
+
+
 END