You can put the location of your properties file onto the server classpath and you should be able to access it using
Code:
<bean id="messageSource" class="org.springframework.context.support.Reloada bleResourceBundleMessageSource">
<property name="basename" value="classpath: nameOfPropertiesFile" />
</bean>
If you are using Websphere, you can setup a "Shared Library" in the admin console that points to a folder, this will add it to your server classpath.
Another (better IMHO) way would be to use a build tool like Maven. Using profiles in Maven, you are able to define all the entries in your properties files as variables. When you build for a specific environment, Maven will write the environment specific values into your properties file. That way you will have only 1 properties file for each environment (although you will have a separate ear/war for each environment).
hope that helps.