We have began enabling the required code for map autodownload internally and will get these out in an update once we are sure they are working properly, most likely with instructions on their correct usage.
Basically, the maps needs to be setup into a zip file with a specific folder structure, so they are extracted into the correct place by the autodownloader. The autodownload also needs an http host for the files, its not actually the server itself that sends the map out, it just provides a link to the game client, which then downloads the zip from this host location and extracts it..
The setup involves adding a cvar(net_mapDownloadURL) to the levelrotation xml section for the map in question(or manually settings it on the server at map load), the cvar points to the download link containing the zipped copy of the map.