Originally Posted by
wirespot
For it to be plug and play you'd need additional functionality, such as udev or supermount etc. I don't think any of those are installed. The closest you come to "plug and play" is that the 500gP will recognize the external HDD as part of the bootup procedure and mount it under /tmp/harddisk. But not on the fly.
So if you want it mounted without extra intervention, just plug it in and power-cycle the router. Provided the firmware bootup procedure is clever enough, it will be mounted.