I have tried to copy files using an external HD and i could not see the HD on the BS5. I have tried to turn of the firewire/1384, asign different drive letters to the other drives and God know what. Nothing helped until one friend of mine told me that he had experiencesd the same and found out that it was because the external HD was requiring more power through the USB than what could be delivered. I therefore found one of those USB cables where you have two plugs - one normal and one for power, connected the power one to another computer and VOILA.

Just in case any other is struggling with this.