Hi Ramakrishna,
FPAYH-INTAD is the clerks's Internet address (LFB1-INTAD) and not the vendor email address.
If you Need the Clerks Internet address, just map the structure field FPAYH-INTAD in the DME node (obviously the value Need to be there in the vendor master data "correspondence tab" for the DME to disply it).
if your requirement is to populate the Vendor email address, then you Need to write a user Exit.
ADRNR value. With this value go to table ADR6 and get the value of ADR6-SMTP-ADDR field and Display it. Take help from ABAPer to get this done, if required.
Once written, assign the user Exit in the DME node
Check what your requirement is and act accordingly.
BR
Amitash