>vnconfig -t floppy3 -v -c /dev/vnd0d boot.fs
>vnconfig: /dev/vnd0d: opendisk: Device not configured
>*** Error code 1

You need a line similar to the following in your kernel conf file.

pseudo-device   vnd 4                   # Vnode devices

-- 
Phil Nelson                    NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu        !gifs: http://www.gnu.org/philosophy/gif.html
http://www.cs.wwu.edu/~phil