I wanted to pass along info to this thread based on my ESRI Tech Support call on 11/26/13. My call was to solve why my template MXDs were not showing up in the ExportWebMap task. During the call I was shown how to set and resize the legend for my map and set it to fixed frame. Upon experimenting with the resulting PDFs, the legend worked fine and displayed the full legend of any items currently visible on the map. Please feel free to follow up in this thread if you need any assistance with setting up any parameters.
My current dilemma is trying to figure out how the ordering of items in the published service impact the legend display. I've read via Help documents that if an items is to large to display in the fixed frame box, then that layer's legend items will not be shown. However, based on my tests, if I have our Zoning layer active (25+ categories) then the fixed frame box displays nothing in the legend, almost as if it overwhelms the template. Still experimenting.....
Best regards,
-Matt