Add new field in outgoing bank DME file

Hi SAP FICO friends,

I need your help in below issue resolution.

After executed F110 transaction, DME file is generated for outgoing payment. Now client is requested for Add a new field (value date) in DME file. Please let me know how to add this new field in DME config? Already I have checked DMEE transaction, under the keyfield structure tab (4th tab), But I could not succeed to how proceed to add this field.

Please let me know with complete details. Thanks,

Raj