[144342] changing to use UNSET_VALUE
diff --git a/plugins/org.eclipse.wst.common.emfworkbench.integration/src/org/eclipse/wst/common/internal/emfworkbench/integration/ModifierHelper.java b/plugins/org.eclipse.wst.common.emfworkbench.integration/src/org/eclipse/wst/common/internal/emfworkbench/integration/ModifierHelper.java
index 1020c31..af4883a 100644
--- a/plugins/org.eclipse.wst.common.emfworkbench.integration/src/org/eclipse/wst/common/internal/emfworkbench/integration/ModifierHelper.java
+++ b/plugins/org.eclipse.wst.common.emfworkbench.integration/src/org/eclipse/wst/common/internal/emfworkbench/integration/ModifierHelper.java
@@ -18,6 +18,7 @@
 import org.eclipse.emf.ecore.EPackage;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.impl.EClassImpl;
+import org.eclipse.emf.edit.command.SetCommand;
 import org.eclipse.jem.util.logger.proxy.Logger;
 import org.eclipse.wst.common.internal.emf.utilities.FeatureValueConversionException;
 import org.eclipse.wst.common.internal.emf.utilities.FeatureValueConverter;
@@ -101,7 +102,7 @@
 	public void doUnsetValue() {
 		shouldUnsetValue = true;
 		if (value != null && feature != null && !feature.isMany())
-			setValue(null);
+			setValue(SetCommand.UNSET_VALUE);
 	}
 
 	/**