Why not use the VNC client?

http://my-maemo.com/software/applica...37&fldAuto=802

Enable the "memory card" (or something like that) checkbox in the setup before you connect, and you will be able to copy data from the HDD to your N900 over the network, as you control it remotely from the N900. Sweet! I've used it myself a few times - not as fast as USB of course, but useful nonetheless.