WR703N extroot and swappable storage?

Hi guys,

I wonder if someone could help me? I'd like to do the USB hub mod on my currently working piratebox on an WR703N.

I'll use a USB pen drive internally for extroot (so I have enough space for packages, piratebox etc) and I'd like to have a swappable external filesystem that doesn't contain anything except files for sharing.

Could someone guide me in the direction of what I need to do to make this happen please?

Many thanks,

A_N