Ok so there is actually two different ways of doing this.
1
To add a disclaimer or footer to your company’s outgoing mail, follow these steps:
- Sign in to the FOPE Administration Center.
- Locate the domain to which you want to apply the disclaimer or footer.
- In the Policy Filter Settings section, do the following:
- In the Text Footer field, type a plain text version of the footer or disclaimer that you want to apply. This is the footer or disclaimer text that is applied when a text email message is sent. It will not keep any formatting. Only the text is applied to the footer or disclaimer.
- In the HTML Footer field, type the HTML-coded version of the footer or disclaimer that you want to apply. Or, type the same plain text version of the footer or disclaimer that you typed earlier.
Note Both the Text Footer field and the HTML Footer field must contain a value, even if you want to use only one version of the text.
- Click Save, and then confirm that the text in both fields is saved correctly.
It may take 1.5 hours before the footer or disclaimer is available for use. When it is available, all outgoing email messages will contain the footer or disclaimer.
From http://support.microsoft.com/kb/2639679/en-us?sd=rss&spid=15836
2
Add a disclaimer to all outbound messages
Here’s how to create a disclaimer that’s added to the bottom of all messages sent to external recipients:
- In the Exchange Control Panel, select Manage My Organization > Mail Control > Rules.
- Click New. Enter the following information in the New Rule window:
- Click “More Options…”.
* If… Select “The recipient…” and “is external/internal”. In the Select Scope window, select “Outside the organization”, and click OK.
* Do the following Select “Append a disclaimer to the message…” and “Append a disclaimer”.
- Click “* Enter text…” to enter the disclaimer text, and click OK.
- Click Select one… to specify a fallback action that defines what you want to do if the disclaimer can’t be applied to the message. The choices are Wrap, Ignore, and Reject. The default action is Wrap. To learn more about these options, see Fallback actions.
When you are finished, click OK.
- To add exceptions to the rule so the disclaimer isn’t applied to specific messages, click “* Except if…”. For example, to specify specific users, select “The sender…” and “Is this person” or “Is a member of this group”. For a complete list of the available exceptions, see Conditions and Exceptions for Transport Rules.
- Name of rule Accept the default name, or enter a unique, descriptive name for the rule.
- Click Save.
To read more and configure the look and feel http://help.outlook.com/en-us/140/ff852816.aspx