For the PanelView Plus to see the *.MER file, it needs to be in the "\Rockwell Software\RSViewME\Runtime\" directory on the USB or SD card.
I know that pre-v6 terminals needed the USB or SD card to be formatted for FAT16, but I recently used an 8GB USD driver formatted for FAT32 and it worked with a PV+6 600.
From that removable storage location, you can use the ordinary PanelView Plus configuration menus. Use the File Management menu to copy the file to Internal Storage, use the Load Application button to load the application into memory, then use the Startup Options menu to configure the terminal to run the application at startup.
You don't get the nice automatic "run project at startup" checkbox that you get with the download utility; you have to configure the startup options yourself.
Always test the power-down and reboot features with a real powerdown and reboot; it's easy to inadvertently miss one of the selection boxes.