I would like to be able to do the same. In addition, add support for attaching a USB hard drive. While it is unfortunately a USB 1.1 port, the functionality would be nice.
What makes you think it's a USB 1.1 port?
A long time ago I investigated this, along with the possibility of attaching a USB hard drive, and based on the notes I have been able to dredge up ...
a) the Marvell 88F5181 processor used in hardware rev A1 supports USB 2.0
b) the DMESG output when my DNS-323 boots lists an EHCI (enhanced host controller interface aka USB 2.0)
c) crude read/write tests to a USB 2.0 memory stick showed transfer rates of approximately 10 MByte/sec, well over the 12 mbps speed of a USB 1.1 port.