If I understand correctly what you are trying to do, then is possible in different ways.
One way that always work is dialing the outgoing number and when done the "dial" button. If you start by pressing the "dial" button, then it will look at your digitmap programmed.
Below an example of the digitmap. There are different documents online where the digitmap is explained.
Digitmap x.T|*x.T|#x.T
Digitmap timeout 3|3|3
The T stands for Timeout, that means you would have 3 seconds the time before the phone will dial out.