Auto voice message - outgoing call

Hello,
We want to implement an automated message that will be played on ALL OUTGOING calls before the caller gets connected with called party. For example:
Phase 1: Agent is calling client and hears a ringback tone all the way until phase 3
Phase 2: client answers his phone and hears the message “Hello. We are calling from - company . An agent will be connected in a moment. Please note that this call is being recorded”
Phase 3: Agent gets connected and then starts his conversation with caller.

How can we make that using asterisk?

Use the U option on Dial. I don’t know if the agent gets ringback, or whether than get Answer and silence.