On DefineDosDevice functioning!

Hi there,
I am trying to create a drive for a mapped folder using DefineDosDevice(),
in winxp. After this device is created, the IO manager should pass all IO
requests for this drive to the driver for device\HarddiskVolume1, which is
again the default harddisk (c: in my case). But the IO requests do not
seem to be handled, and I am not able to see the contents of the folder in
the new drive. What is the problem here? Is it required to write a new
driver everytime a device is created using DefineDosDevice, irrespective
of whether its on a local drive or not?

thanks
gs