SVN and ignoring files

Today I branched gnome-power-manager for 2-18. Expect a fair bit of refactoring on trunk, and the self test code to grow in complexity. SVN is different. Why is is so hard to set svn ignore properties? It seems so difficult compared to CVS. Google isn't being helpful either. How for instance do I set the svn:ignore property on “test/.libs” without upsetting the other ignored status of the other files? There must be a GUI for this somewhere. Any ideas?