[Asterisk-Users] Extensions to solve three way calling problem

[PHP Mechanic]

My daughter hates my phone system because she can't use the three way 
function.

What should my extension.conf look like to solve this problem.

Without asterisk I can do the following without any trouble.

1. Establish a call with the first person. You can call them or they can 
call you.
2. Press Three Way, or Flash/Recall on any other touch tone phone to put the 
first person on hold.
3. Wait until you hear the dial tone.
4. Dial the number of the second person.
5. Wait until you hear the second line ringing.
6. Press Three Way or Flash/Recall and talk to the first person (they will 
hear the ringing tone too).

However I have the following setup and I want to be able to do the same 
thing and it just doesn't work.

analog phone <=> asterisk/tdm11b <=> pstn

Can this be done? Does anyone have some extensions they could share with me 
which could achieve the same thing.