It can't be done with hacking the unit - and as far as I am aware - any such hacks are not supported by D-Link and beyond the purview of this forum.
I know people have external USB drives to the DNS-323 via the USB port, but you sound like you want to use the DNS-323 as a portable drive accessing it via USB, I'm not certain that can be done - but - it really all depends on how good a hacker you are.
Google will find you more information.