Hello Srivatsava,
I have made the mentioned changes in mapping file which we have downloaded from Standard scenario on HCI catalog. (I am clueless why you didn't get the mapping file for Preview scenario) But yet I am still getting the No PDF found error in the blank pop up.
So according to my understanding now my XML should have default Y for IV_PRINT_ALWAYS and respective Document Type in IV_KSCHL.
Also the direct mapping exists for IV_VBELN.
Please note that I am using SalesDocumentPrintPreviewQuery instead of ns2:ERP_LORD_GET_PRINT_PREVIEW that you used on both side. Since for us C4C message would be mapped to ECC IDOC.
Hope my understanding is right. Kindly suggest.
Regards,
Chandan