Dear Sarmath,
BBPGETVD tcode is used to replicate vendor from ECC to SRM not from SRM to ECC.
Vendor registered through ROS process should be accepted in ROS and then needs to be transferred to ECC and you can use BBPGETVD to replicate it to SRM. To Replicate the vendor from ECC to SUS/ROS you have to use BD14. Once the vendor has been replicated successfully you can find the relationship in table BBPV_BUPA_VENMAP. VENMAP table will only be updated once you replicated the vendor from ECC.
Please find the screenshot and let me know for any clarification. l
Thanks
Shuvrajyoti