A mobile communication device, comprising a display, a persistent store, at least one input device, and a processor for executing (i) an invoking application for generating a request for document data responsive to an input via the input device, (ii) an attachment viewer for receiving the request and generating a command for chunks of document data, and (iii) a listener interface for receiving a response to the command and passing the chunks to the attachment viewer for displaying respective chunks of said document data via the display.