
An attachment comprises any data (for example, text or graphics) that can be appended to a message. In principle, you can append an unlimited number of attachments to an output message of a consumer or provider proxy (in the synchronous case), using the MessageSpecifier object.
Not all receivers of a message can understand attachments and therefore some receivers will ignore them. The proxy runtime (ABAP/Java) can process attachments, however the majority of the adapters cannot.
You can generate an attachment object using methods of the MessageSpecifier interface. Attachment objects are instances of the class MessageAttachment, which has the full name com.sap.aii.proxy.xiruntime.core.MessageAttachment.