diff --git a/library/IPA_Types.ttcn b/library/IPA_Types.ttcn
index 1636f44..eb8081c 100644
--- a/library/IPA_Types.ttcn
+++ b/library/IPA_Types.ttcn
@@ -37,11 +37,13 @@
 {
 	uint16_t	lengthInd,
 	IpaStreamId	streamId,
+	IpaExtStreamId	streamIdExt optional,
 	octetstring	payloadData
 } with {
 	variant (lengthInd) "LENGTHTO(payloadData)";
 	variant (lengthInd) "FIELDLENGTH(16)";
 	variant (lengthInd) "BYTEORDER(last)";
+	variant (streamIdExt) "PRESENCE(streamId=IPAC_PROTO_OSMO)";
 }