Eclipse Project => Deployment Assembly or Equivalent for GWT Web Application?

_This issue was originally filed under gwt rather than the gwt-eclipse-plugin, so recreating here:_

We use Eclipse for GWT development. We have several existing projects that are defined as GWT Web Applications and are run via the GWT Plugin in either Super or Classic Dev Mode. We've found a problem which is that our project build path (.classpath) refers to JARs at various locations outside the WEB-INF/lib directory, but running (Super)DevMode via the plugin doesn't copy those JARs to WEB-INF/lib. The result is that the app fails out with ClassNotFound exceptions.

In a "normal" Eclipse Java Project, say one defined as a "Dynamic Web Module," you can configure part of the project properties called "Deployment Assembly" to copy the JARs you want to WEB-INF/lib. Indeed, if I define and run the GWT CodeServer separately, and deploy the app to Tomcat or Jetty manually using a Dynamic Web Module project I can solve it that way.

However, I'd like to use the built-in jetty server for GWT SDM since that's what our customers will do. How can I achieve what I need? Obviously, the files can be copied by hand in the OS, and that's what we do now, but I'd like a better solution. I'm also aware that Maven and/or IvyDE have the potential to solve this, but I'm not interested in adding Maven or Ivy to the equation just to solve this issue.

Can someone tweak the GWT Plugin source defining a Web Application to enable "Deployment Assembly," and make sure it's triggered when the GWT Plugin is used to run (Super)DevMode?

Note, I've already tried manually adding the appropriate configuration to the .classpath XML file that gets added when you tinker with the Deployment Assembly page, but it doesn't work. I assume this is because the "run" button of the GWT Plugin doesn't trigger the critical logic that reads and acts upon the extra .classpath config data. This critical logic, however, clearly does run if you tell Eclipse to deploy a Dynamic Web Module to Tomcat (for example).

Thanks.