Index: /apps/workspaces/main/xstream/src/java/com/thoughtworks/xstream/core/DefaultConverterLookup.java
===================================================================
--- /apps/workspaces/main/xstream/src/java/com/thoughtworks/xstream/core/DefaultConverterLookup.java	(revision 712)
+++ /apps/workspaces/main/xstream/src/java/com/thoughtworks/xstream/core/DefaultConverterLookup.java	(working copy)
@@ -12,6 +12,11 @@
 import java.util.Iterator;
 import java.util.Map;
 
+/**
+ * The default implementation of converters lookup.
+ * 
+ * @author Guilherme Silveira
+ */
 public class DefaultConverterLookup implements ConverterLookup {
 
     private final PrioritizedList converters = new PrioritizedList();
@@ -46,6 +51,12 @@
     
     public void registerConverter(Converter converter, int priority) {
         converters.add(converter, priority);
+        for (Iterator iter = this.typeToConverterMap.keySet().iterator(); iter.hasNext();) {
+			Class type = (Class) iter.next();
+			if(converter.canConvert(type)) {
+				this.typeToConverterMap.remove(type);
+			}
+		}
     }
 
 }
Index: /apps/workspaces/main/xstream/src/test/com/thoughtworks/xstream/core/DefaultConverterLookupTest.java
===================================================================
--- /apps/workspaces/main/xstream/src/test/com/thoughtworks/xstream/core/DefaultConverterLookupTest.java	(revision 0)
+++ /apps/workspaces/main/xstream/src/test/com/thoughtworks/xstream/core/DefaultConverterLookupTest.java	(revision 0)
@@ -0,0 +1,27 @@
+package com.thoughtworks.xstream.core;
+
+import junit.framework.TestCase;
+
+import com.thoughtworks.xstream.converters.Converter;
+import com.thoughtworks.xstream.converters.SingleValueConverterWrapper;
+import com.thoughtworks.xstream.converters.basic.StringConverter;
+import com.thoughtworks.xstream.mapper.DefaultMapper;
+
+/**
+ * @author Guilherme Silveira
+ */
+public class DefaultConverterLookupTest extends TestCase {
+
+	public void testConverterChange() {
+		final DefaultConverterLookup lookup = new DefaultConverterLookup(
+				new DefaultMapper(Thread.currentThread()
+						.getContextClassLoader()));
+		Converter currentConverter = new SingleValueConverterWrapper(new StringConverter());
+		lookup.registerConverter(currentConverter, -100);
+		assertEquals(lookup.lookupConverterForType(String.class), currentConverter);
+		Converter newConverter = new SingleValueConverterWrapper(new StringConverter());
+		lookup.registerConverter(newConverter, 100);
+		assertEquals(lookup.lookupConverterForType(String.class), newConverter);
+	}
+
+}