10. A device for communicating multiple files in a single markup language document, comprising: one or more processors for executing a document interface, the document interface operable to receive electronic data for delivery to a destination address, to receive an electronic file associated with the electronic data, to generate a first markup language document including the electronic data, to store both the first markup language document and the electronic file in a payload of a second markup language document, to generate a header for the second markup language document, the header identifying the existence of both the first markup language document and the electronic file in the payload, the header comprising at least one parameter indicative of one or more relationships between the first markup language document and the electronic file in the payload, and to transmit the second markup language document including the header and the payload to the destination address using a communication network.
13. The device of claim 10 , the document interface further operable to receive a first inbound markup language document including an inbound header and an inbound payload, to determine that the inbound header identifies both a second inbound markup language document and an inbound electronic file in the inbound payload, to access the second inbound markup language document in the inbound payload, and to access the inbound electronic file in the inbound payload.