I just downloaded the Springsource Tool Suite, and I created a simple bean configuration file called myDefinition.xml and placed it in the root directory of the Spring Project.
In the Spring Explorer tab in Eclipse, right click on your project > properties. Then go to Spring > Beans Support and select the Config Files tab. You can then select files or scan a directory and that should add them. I haven't found a way to autoscan a directory so I don't have to do this whenever I add a new spring bean file. The beans that appear in that list are stored in the .springbeans file.