How to supress drive letter assignment??

I have a driver that is integrated with the mount manager and is creating
new volumes. As it creates new volumes, W2k insists on assigning them a
drive letter. I can’t find anything in the mount manager documentation on
how to prevent this. I don’t want them to have drive letters because they
are later given mount points in user mode. Of course I could just remove
the drive letters, but there ought to be some way to prevent them from
being assigned in the first place.

I looked at IOCTL_MOUNTDEV_QUERY_SUGGESTED_LINK_NAME and at
IOCTL_MOUNTMGR_AUTO_DL_ASSIGNMENTS. Both of these can assign a drive
letter, but not supress it.

Any ideas would be appreciated.

Thanks,

Don