You will need IP Plus software on the routers. Be sure to check the memory requirements for the Plus image, you will probably need at least 32MB of Flash.
In CallManager, under the gateway, make sure you have the appropriate numbering plans setup. If you leave them as CallManager, The Telco may reject the IE. So in North America you would set the Calling Party IE Number Type Unknown to National and The...
If you just want to block the DID info on calls to the PSTN for select phones, use the external phone number mask in the phones DN properties. Make sure you set the route pattern to accept this as well.