Setup an IPSEC VPN between the two sites. Then setup dial-peers with the destination-pattern being the extension scheme for each site.
Also, set the session target for each dial-peer to the ipv4 of the data vlan
dial-peer voice xxx voip
destination-pattern 3..
session target ipv4:10.10.10.10
dial-peer voice xxx voip
destination-pattern 5....
session target ipv4:20.20.20.20
You can also setup the incoming dial-peers for each site. Let me know if you need any further help!
-Trent Good
** Please rate useful posts! **