Sorry, the standalone CBC/HB software just outputs a CSV and an HBU file of the raw utilities. If the analysis is done inside of SSI Web, such as ACBC analysis, you are given an option to save a spreadsheet where one tab includes importance scores.
But, you don't need to calculate them manually. You can create a study in the SMRT software and import the HBU file, then turn right back around and export a CSV file of importance scores. A second option would be if you have an account at www.sawtoothsimulator.com, you can upload either the HBU file or the CSV file from CBC/HB, and then again download a CSV file of importance scores (or make nice graphs and save those).
In the next release of version 8, 8.0.4, analysis has been integrated inside of SSI Web, so you will get the same multi-page spreadsheet output for normal CBC studies (including importance scores) like you do for ACBC. 8.0.4 is a free upgrade for existing version 8 users.