Service Interface - External Fault Message

Hello,

I am working on a RFC to SOAP scenario. I do have 2 external fault message type in an operation for service interface, all mappings are done and mappings are defined in operation mapping. But when i trigger RFC and Web Service returns fault message, i am getting "NO MAPPING PROGRAM FOUND ERROR". 

When i remove 1 of those external message type from service interface, and from operation mapping, it works just fine. Is it not possible to use more than one external fault message in Service Interface to not to get a System Error?

Thanks.