Play an annoucement

Hello everybody,

can anybody share a simple callflow for call setup phase announcement playing in a peering environment?

I'd go for something like this (if it's possible), but any other proven solution would be great: a call hits SBC, SBC routes the call to OCCAS, OCCAS triggers MRF and it plays an announcement to the calling pty. OCCAS then sends:

1. an INVITE to route the call to the final destination and

2. another INVITE to the SBC with a REPLACES header to link the call leg from 1. with the initial INVITE from calling party.

In other words the OCCAS should not be involved in the entire call, but in its setup phase only....because of licenses:).