Using a Toshiba Gigabeat MEGF-40 (tried several version of RockBox) I had the same problem.
Edited /usr/share/hal/fdi/preprobe/10osvendor/20-libgphoto2.fdi as root
Searched for Gigabeat MEGF-40
A few lines before, It has:
<match key="usb.vendor_id" int="2352">
<match key="usb.product_id" int="9">
the command "lsusb" showed:
Bus 001 Device 011: ID 0930:0009 Toshiba Corp. Gigabeat F/X (HDD audio player)
I changed the 2352 to 0930
Plugged in my toshiba and it popped up on the desktop.
Thanks so much for the help, I look forward to the package in an update!