Hello Exclusive OR,
You cannot do this directly like you can with other .NET applications, but you should be able to accomplish the same thing by adding an XML Document as a secondary data source.
1. Go to tools -> Data Connections -> Add
2. Recieve, Xml Document, filepath, Finish
3. A dialog will pop up asking whether you would like to add the file to the form template. Click NO.
Now the template references this file from wherever it is deployed. You can change values inside this XML file whenver you like and the next time the template is opened it will see these changes. You will probably want to put the config XML file in a network accessible folder.
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge