I'm currently using this CAS screen in my own game. You need all the expansion packs up to and including Open for Business ( + Uni, + NightLife).

To use a custom CAS: Download the .rar file to your computer. Extract the CAS! file and place it in your downloads folder (...WhateverYouCallYourMyDocuments/EA Games/The Sims 2/Downloads). You can only have 1 set of custom CAS! and YACAS! in your downloads folder at a time. So remove any other ones you might have before adding this one. This is only the main CAS and not the a Uni one (YACAS!).