You can include a previously excluded company so that they do appear in the communication log, the following video explains how to do this. There are step-by-step instructions below the video.
Steps
Open CRM.
Click on Leads (Comm Log).
Click on the Filterbutton to view all excluded companies.
Select thecompany you wish to include.
Click on the Grid Actions button.
Select the Put Company back to Communications Log.
Click Continue in the popup.
Click on the Filterbutton and turn the excluded filter off.