Help getting Canon LiDE 30 USB scanner to work

[Vincent Stemen <vince.dragonfly@xxxxxxxxxxx>]

We had this scanner working once before with an earlier version of
Dragonfly but do not seem to be having any luck now.

sane-find-scanner  says it found the scanner
    found USB scanner (vendor=0x04a9 [Canon], product=0x220e [CanoScan], 
    chip=LM9832/3) at libusb:/dev/usb1:/dev/ugen0

but

scanimage -L  says
    No scanners were identified.

Environment:
    Dragonfly version: 1.10.1-RELEASE
    sane-backends-1.0.18
    libusb-0.1.12nb1 is installed.  

uscanner is compiled into the kernel according to kldstat.  

I am unclear as to whether this can conflict with libusb or under what
conditions it is required.  The sane docs say to use libusb but they are
fairly Linux centric.

The manual on sane-usb says

    Libusb  can  only access your scanner if it's not claimed by the
    kernel scanner driver. If you want to use libusb,  unload  the
    kernel  driver (e.g. rmmod scanner under Linux) or disable the
    driver when compiling a new kernel.

Does this apply to Dragonfly?  I found no section on scanners in the
Dragonfly handbook but the FreeBSD handbook says the oposite.  It says
that you should have the uscanner module loaded.  If sane requires
libusb, I am unclear about the purpose of the kernel uscanner driver.
It is built into the kernel, so I have not tested without it yet, since
I would have to compile a new kernel rather than just unloading it as
a module.  Unless there is some way to disable a compiled in module that
I don't know about.  

I also added this to /usr/pkg/etc/sane.d/genesys.conf
    # Canon LiDE 30
    usb 0x04a9 0x220e

But it had no effect.