extending vg on a resized pv

[Maurizio Marini]

Using vmware I have enlarged the second disk /dev/sdb of a virtul
machine,adding 5 Giga to actual 20 Giga; then using pvresize:

pvresize -v /dev/sdb
    Using physical volume(s) on command line
    Archiving volume group "vgopt" metadata (seqno 2).
    Resizing physical volume /dev/sdb from 5119 to 6399 extents.
    Resizing volume "/dev/sdb" to 52428416 sectors.
    Updating physical volume "/dev/sdb"
    Creating volume group backup "/etc/lvm/backup/vgopt" (seqno 3).
  Physical volume "/dev/sdb" changed
  1 physical volume(s) resized / 0 physical volume(s) not resized

sofar no prob.
# vgs
  VG         #PV #LV #SN Attr   VSize  VFree
  VolGroup00   1   2   0 wz--n-  7,88G    0 
  vgopt        1   1   0 wz--n- 25,00G 5,00G

vgopt is 20G large, how can i extend it to use extra space?

thnx for any suggestion


-- m.