diff --git a/library/Osmocom_Gb_Types.ttcn b/library/Osmocom_Gb_Types.ttcn
index ee1437c..8271ced 100644
--- a/library/Osmocom_Gb_Types.ttcn
+++ b/library/Osmocom_Gb_Types.ttcn
@@ -1296,16 +1296,17 @@
 		}
 	}
 
-	template PDU_BSSGP tr_BSSGP_DL_UD := {
+	template PDU_BSSGP tr_BSSGP_DL_UD(template (present) GprsTlli tlli, template (present) octetstring pdu,
+					  template IMSI_BSSGP imsi := omit) := {
 		pDU_BSSGP_DL_UNITDATA := {
 			bssgpPduType := '00'O,
-			tLLI_current := ?,
+			tLLI_current := tlli,
 			qoS_Profile := ?,
 			pDU_Lifetime := ?,
 			mS_Radio_Access_Capability := *,
 			priority := *,
 			dRX_Parameters := *,
-			iMSI := *,
+			iMSI := imsi,
 			tLLI_old := *,
 			pFI := *,
 			lSA_Information := *,
@@ -1321,7 +1322,7 @@
 			old_Routing_Area_Identification := *,
 			attach_Indicator := *,
 			alignment_octets := *,
-			lLC_PDU := tr_BSSGP_LLC_PDU,
+			lLC_PDU := tr_BSSGP_LLC_PDU(pdu),
 			initialLLC_PDU := *
 		}
 	}