Business Connector-Mapping Records

I am working on a requirement in BC, where we are receiving Idoc from SAP and the output from BC should be in a third party XML format.

I have configured routing rules with B2B service and created a folder and a service. In the service I have captured the IDoc into a record structure. Also the record structure of the third party is available.

But while mapping the values from the Idoc record structure(source) to the third paty record structure(target) values are not flowing from the source to the target.

And the target structure shows null values eventhough the source structure has values.

Please point out what I am missing.

Thanks in advance.