JBIDE-1354 should provide the possibility to save runtime configurations. These configurations are stored in the paths .plugins/org.jboss.ide.eclipse.as.core/.global/filesets/runtimeClasspaths/org.jboss.ide.eclipse.as.runtime.32 etc.
However, there is only the path .plugins/org.jboss.ide.eclipse.as.core/.global/filesets/default and additions to a runtime like "JBoss 7.x Runtime" are not possible. If I manually create the path .plugins/org.jboss.ide.eclipse.as.core/.global/filesets/runtimeClasspaths, then a new entry can be added and there is e.g. org.jboss.ide.eclipse.as.runtime.70.