Go into Preferences ( Ctrl-P ) and on the Configuration tab go to the Scan tab - then add a comma and .7z into the media extension box - place a check mark in the Force rescan of media folder (this makes Maximus scan the folders on next launch - close the box. (Not sure but at this point you may need to close Maximus and restart it - to get it to rescan the folder and add the 7 zip files it finds.
Once it restarts and the files are there go back into preferences and uncheck the Force rescan box (otherwise it will scan every time you start Maximus which can slow the loading !! )