SLED field is blank in IDoc type WMMBXY

Overview:

We need to enable SLED check while GRN and Goods issue of material. Have done configuration and all business scenario are working fine.

Technical names of both fields are:

SLED:                                         MSEG-VFDAT

Manufacturing Date:                     MSEG-HSDAT

Our SAP is linked with 3PL systems through EDI (IDOCs). So we have to send  thes 2 dates to 3PL throgh Idocs. Technical details of outbound idoc are:

Idoc Basic type:                                 WMMBID02

Idoc Message Type:                        WMMBXY

Issue:

While we good issue with movement type 351, idoc is created but Field HSDAT is not appearing in idoc and field VFDAT is there but no value passed to it, means it is balnk.

Pls help.