mount_msdosfs usb flash stick

[joeb]

On 6.2 release of FBSD trying to mount a usb flash memory stick. The stick
has a msdos file system on it and has been loaded with files using windows
xp. When I plug the stick into my FBSD box I get console msg about da0
device as usb flash memory stick. All looks good at this point. When is
issue this command,  mount_msdosfs /dev/da0 /mnt  I get this error msg  '
invalid argument' .  Also tried this format of the command with same
results.    mount -t msdo /dev/da0 /mnt


What am I doing wrong here?