Hi - My first post on this site. Gday!

Does anyone know a hack to allow me to add my pre written sentences to the My Text Messages option.

To clarify....

When you open new text message, there is an option to use a pre written common sentance or word such as "Please call my mobile" or "yes" or "no" or "please call home" etc.
There is only one spot left where you can add your own.
You can however edit one of the existing ones.....

My question is how do I add more to this section?