unable to boot squashfs through mtd device

Hi,

I have built latest qemu archive qemu-1.1.1 to be sure of up to date source code.
I have then built buildroot squashfs image, which can be used correctly with cmdline like:

qemu-system-i386 -m 64 -k fr -boot c -kernel images/bzImage -drive if=ide,file=images/rootfs.squashfs  -append "root=/dev/sda"

Then I wanted to modify cmdline to use real MTD device, like:

qemu-system-i386 -m 64 -k fr -boot c -kernel images/bzImage -drive if=mtd,file=images/rootfs.squashfs  -append "root=/dev/mtdblock0".

But nothing was good under kernel.
Even if mtd0 is reported through qemu interface (Ctrl Alt+2), no device can be found under kernel even if all drivers are built to use it.

Is this feature okay on qemu-1.1.1 ??
did I do mistake in my cmdline??

thank you for your help.
regards,