Adding a new slice, problem with sysinstall

1. Create a new slice : sysinstall->Configure->Fdisk

2. Make sure only one ACTIVE slice ( partition )
fdisk /dev/ad0
fdisk -a -1 /dev/ad0

3. Add a 'standard' label, remember disks start from zero, but slices start
from one!:
# bsdlabel -w /dev/ad0s3

4. Edit the label:
# bsdlabel - e /dev/ad0s3
Change fstype on the line beginning a: from unknown to 4.2BSD, then save
and exit.

5. Format the new partition:
# newfs /dev/ad0s3a

6. Test mount the partition:
# mount /dev/ad0s3a /mnt

7. Edit /etc/fstab. Add a new line similar to the line for /dev/ad0s2a.
Careful! getting fstab wrong can prevent your system starting.
Test the new fstab with # mount -a.