Bundleless Builds
If you use WOLips' "Bundleless Builds" feature, then you don't need to configure RuleModeler.app to work with Eclipse, because with that feature turned off, Eclipse no longer needs to be slapped upside the head to catch changes to the .d2wmodel files.
To configure rule modeler to work with the Eclipse/WOLips toolset during D2W development, you need to first set up the WOLips server in Eclipse preferences under WOLips->WOLips Server
Once the server is setup, open Rule Modeler and in the rule modeler preferences, enter your password and port number there.
If you do not do this, you must Refresh your workspace in order to get new rules to apply.