Put a small dab of hot melt glue on the other side of the standoffs and place the circuit board inside the case. Now put some super glue on the side of the slot you cut for the telephone jack and slide it into place. Lastly, glue the battery case to the inside of the lid. Position it so that it will fit over the circuit board when the lid is closed. You need to test every connection as you go along, and double and triple-check everything.
Every connection is a possible point of failure.
If you re comfortable with electronics and have a desire to hack around, this project is probably for you. If your idea of a serial connection is a bowl of Cap n Crunch, you probably shouldn t be doing this. I know it can be done. However, I can t promise that you ll have success if you try. I also can t promise that I ll be able to help if you try it and can t get it working.