Software Deployment

I am using Install shield 9, and currently my install package will look at the size of my installation directory for information on what to display under add/remove programs. However, my program makes some log files and puts them in that directory, so sometimes that number is not entirely correct. I only want to display the actual size of hte program I installed, not any extra things in the directory.

I know there is a registry key called "EstimatedSize" which looks like the correct size of my program, but I don't know how to get my installshield project to utilize that number.

Any help is greatly appreciated! [:D]