USB compisite devices

[VirtualAdam]

I am trying to connect Lexmark X2350 printer/scanner to VirtualBox's guest OS: in this case - Windows XP (because there are no Lexmark drivers for Mac OS X). This is USB composite device with 3 interfaces: scanner, printer, and HID (for machine's buttons). First of all, I have to manually adjust USB filter, removing "Serial", but that's okay. I get the device connected to the guest, but the scanner doesn't work. I see there's some communication, because the USB icon flashes, but still, scanning is impossible. Exactly the same virtual machine works normally on VMware Fusion trial.

Please, advice.