The VG200 works fine as an H323 gateway. The configuration you need really does depend on what you are trying to do, but the following is an example that may help. Don't forget to have the "ip routing" statement somewhere in your config or you will have very bad or no speech quality.
If you are bouncing through router hops too, as well as setting up QoS you will need to bind the correct IP address for VoIP to your VG200s LAN interface using something like this:
h323-gateway voip bind srcaddr 192.168.32.1
Sample follows with output omitted....
!
voice class codec 1 # preferred codec sequence (only if required)
codec preference 1 g711alaw
codec preference 2 g729r8
!
voice class h323 1 # a way of modifying this setting (only if required)
h225 timeout tcp establish 3
!
voice-port 1/0/0 # the physical port settings
compand-type a-law
cptone GB
codec g711alaw
!
voice-port 1/0/1 # the physical port settings
compand-type a-law
cptone GB
codec g711alaw
!
dial-peer voice 300 voip # the logical settings for o/g numbers dialled with a leading "1" and 3 other digits
preference 1
destination-pattern 1...
progress_ind setup enable 1
voice-class codec 1
voice-class h323 1
session target ipv4:192.168.32.32
dtmf-relay h245-alphanumeric
!
dial-peer voice 301 voip # the logical settings for o/g numbers dialled with a leading "4" and 3 other digits
preference 2
destination-pattern 4...
progress_ind setup enable 1
voice-class codec 1
voice-class h323 1
session target ipv4:192.168.32.32
dtmf-relay h245-alphanumeric
!
dial-peer voice 1 pots # associates a DN of "5000" to this physical voice port
destination-pattern 5000
port 1/0/0
!
dial-peer voice 2 pots # associates a DN of "5001" to this physical voice port
destination-pattern 5001
port 1/0/1
!
