Integrating SOAP web service from SAP Netweaver

Hi, I am new to SAP integration. Actually I am providing a web service (SOAP 1.1). The development platform for the web service is .NET (WCF). The interfacing requires som input data and some output data. In the interface specs, I am defining them as some classes for my use and I can expose them in the payload using message serialisation. But the SAP team wish that I provide the output not as multiple attributes and rather give a single string output with a delimiter (@ in this case) for all the output parameters. The logic behind this is as per the SAP team is a technical limitation of SAP. I could not buy this logic.

I shall like to know if there is any issue for this or how it should be done. Looking forward for your feedback.