Good reference:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124newft/124t/124t2/ht1vg224.htm#wp1027265
Here is a sample config for one of my VG224s
stcapp ccm-group 1
stcapp
!
sccp local FastEthernet0/1
sccp ccm 192.168.1.30 identifier 2 priority 2 version 4.1
sccp ccm 192.168.4.20 identifier 1 priority 1 version 4.1
sccp
!
sccp ccm group 1
associate ccm 2 priority 2
associate ccm 1 priority 1
!
!
dial-peer voice 20 voip
!
dial-peer voice 1 pots
service stcapp
port 2/0