How to auto-mount "sparse image" on external hard drive once connected to the mac?

I have created an encrypted sparse image in my external hard drive, so that when I double-click the image it will prompt for the password, which then I type it in and allows me normal access to my drive.

However, I'd like to find out if I could write a script or do something so that I will be asked for the password once the hard drive is plugged into my mac. I know all I'm doing is skipping the step of double-clicking the image, but I want to know how to make that happen in a DIY way.

Can anyone help me?

Thank you.


-JC