Schema for ebMS-3 XML Infoset This schema defines the XML Infoset of ebMS-3 headers. These headers are placed within the SOAP Header element of either a SOAP 1.1 or SOAP 1.2 message. The eb:Messaging element is the top element of ebMS-3 headers, and it is placed within the SOAP Header element (either SOAP 1.1 or SOAP 1.2). The eb:Messaging element may contain several instances of eb:SignalMessage and eb:UserMessage elements. However in the core part of the ebMS-3 specification, only one instance of either eb:UserMessage or eb:SignalMessage must be present. The second part of ebMS-3 specification may need to include multiple instances of either eb:SignalMessage, eb:UserMessage or both. Therefore, this schema is allowing multiple instances of eb:SignalMessage and eb:UserMessage elements for part 2 of the ebMS-3 specification. Note that the eb:Messaging element cannot be empty (at least one of eb:SignalMessage or eb:UserMessage element must present). In the core part of ebMS-3 specification, an eb:Signal Message is allowed to contain eb:MessageInfo and at most one Receipt Signal, at most one eb:PullRequest element, and/or a series of eb:Error elements. In part 2 of the ebMS-3 specification, new signals may be introduced, and for this reason, an extensibility point is added here to the eb:SignalMessage element to allow it to contain any elements. if SOAP 1.1 is being used, this attribute is required if SOAP 1.2 is being used, this attribute is required