virtualbox - Getting an old USB device (projector) to work through a VM

I have an AIPTEK T20 Pocket Cinema projector (which I bought in 2009, and officially went out of production in 2012). It used to work back in the day when I had Windows XP installed on my computer. However, I now use Windows 8 and even after installing the Windows 7 driver nothing is working (it says "driver unavailable"). On Microsoft's own compatibility guide, it says "no info" and there is one vote for "compatible with Windows 7" (and none against) and one vote for "not compatible with Windows 8" (and none for).

Since it showed no willingness to cooperate at all, I thought I'd fire up a virtual machine with Windows XP on it and connect the USB device to that. This causes the projector to blink for a brief second (it used to blink two or three times before it showed a picture). I haven't tried the same procedure with Windows 7 since I don't have the disc at where I am now - though I doubt that that should have a bigger chance of working(?).

In the virtual machine, it sometimes shows up as a monitor. The driver from the projector installs, everything seems like it used to until I actually try to use it ... When I check the "Extend my Windows desktop onto this monitor"-box and press apply (see screenshot), the checkbox just gets cleared. The same thing happens if I check the box and then check the box above it. No error message or anything, it just does not happen. The projector appears as an option even if I unplug the USB cable itself.

Since it registers as a monitor like it used to back in the day, should it not work? And what are the real differences between attaching a USB device to a virtual machine - are there some things that just won't work anyway for various reasons?

I can't always check the boxes (there are two) for connecting the device to the VirtualBox either. I think it is interesting that it sometimes shows up as two (or even three on rare occasions, two of which have the same name in that case) devices on the VirtualBox device list (one is "busy" and the other one is "captured", whatever that means). The one that is "captured" shows up on the device list even though the projector itself is disconnected, and so does the corresponding devices in the Windows device list (one is "USB Projector Extended" and the other one is "USB Projector Mirror".

When it won't connect to the VM, I get

Result Code:

E_INVALIDARG (0x80070057)

Component: HostUSBDevice

Interface: IHostUSBDevice {173b4b44-d268-4334-a00d-b6521c9a740a}

The projector comes with a "CD function" (it has a switch on the back side) which will cause the projector to register as a drive (which has a driver installer on it). That seems to be working perfectly.

Right now I don't have a computer available for installing Windows 7 (or Windows XP for that matter), so there is now way of really knowing whether or not it is actually broken. In either case I'd like to hear your thoughts on this. So far the only progress I have made is to get it to blink once, and another time I got it to just permanently show a frozen picture with a black bar on the top and on the bottom.