Many add-ins for use with ipSentry are available for trial use to insure that the functionality they provide is indeed the functionality you desire.  When you purchase the license to use these add-ins, they normally come in the form of a serial number or registration code that removes any time-outs or functional limitations imposed by the trial version. 

The standard method to enter registration (license) codes for add-ins is as follows.

1. Select Add-In Manager from the Add-Ins menu.
    

2. Highlight the add-in to be licensed.
    

3. Hit the About Add-In button. 
    

4. You should be presented with an option to register, modify, or otherwise enter a license code.

The method above also provides additional information about the add-in such as Author, publisher, version information, additional quick help, and etc.  This is basically the same as the standard Help/About functionality included with many Windows applications.