The only way that I've ever been able to label second (or n'th) disk has
been to do:
  # disklabel -e sd3

  :w! /tmp/k1
  :q

  # disklabel -w -r cp3100new sd3
  # disklabel -e sd3
  :1,$d
  :r /tmp/k1
  :wq

  There must be a better way to get the initial label on the disk using
disklabel -e. If I use disklabel -e -r, it doesn't usually work.

   :!mcr!:            |  Network and security consulting/contract programming
   Michael Richardson |         Firewalls, TCP/IP and Unix administration
 Personal: mcr@sandelman.ottawa.on.ca. PGP key available.
 Corporate: sales@sandelman.ottawa.on.ca. 
	ON HUMILITY: To err is human, to moo bovine.