can you preload properties before sending request?

Tks for the reply. For clarity, I have a properties file as a test step, I'd like to use say a start-up script to pull all of those properties, and update the soap request so that instead of #phone-number I would see the actual phone number. Does that help? Your response suggested editing the file prior to launching the gui. Id like to be able to update a properties file, and during start-up, update the request.