Hi
To achieve this, you need to use the User Defined fields.
Click on the User defined fields button from the Set Up screen, in the new window click on New. Please then configure the required template and save.
In the disclaimer editor in each rule, click on the {fields} button and select {User Defined} and click on the UDF created in the step above. Uncheck the "Insert field content" button at the bottom of the window.
Each time you update the UDF, it will automatically update in each rule.
For further information of UDF, please refer to the Mail Utilities manual found here:
http://www.exclaimer.com/documentation.aspx
Best Regards
Joshua Clarke
Exclaimer Support