call waiting indication to caller

Hello, In Europe when you call a number that is in use but has call waiting you get a special "ring tone" basically the regular ring is a beep, and a call waiting ring is a stuttered beep. When internal extensions call to the person is on the phone (another extension or extarnal phone like cellular over SIP Trunk) if I have call waiting enabled all I get is a regular been (like a regular ring). We want to have a different ring tone (that caller hear) when call waiting is enabled. It's need to work for all existing extensions and all new extension that we will add in future. Maybe this link will help. [login to view URL]