Central Contract Distribution - Supplier ID is not in XML Payload

Hi guys

We are trying to distribute Central Contract from SRM to ECC. After the contract is released and when I check SXMB_MONI, in payload, I can see all data except the Vendor ID.  The tag <SellerParty> <Internal ID> blank  </InternalID> </SellerParty>.

Can someone say why the Vendor is not passed into the XML message?

Thanks for your input

Srini J