diff --git a/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.rnc b/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.rnc
index 6c0b3763e7..124798d334 100644
--- a/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.rnc
+++ b/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.rnc
@@ -400,9 +400,9 @@ port-mappings.attlist &= empty
 port-mapping = 
     element port-mapping {http-port, https-port}
     
-http-port = attribute http {xsd:integer}
+http-port = attribute http {xsd:string}
 
-https-port = attribute https {xsd:integer}
+https-port = attribute https {xsd:string}
 
 
 x509 = 
diff --git a/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.xsd b/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.xsd
index b9e9733af1..34844f4a38 100644
--- a/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.xsd
+++ b/core/src/main/resources/org/springframework/security/config/spring-security-2.0.4.xsd
@@ -876,8 +876,8 @@
     </xs:attribute>
     <xs:attribute name="requires-channel">
       <xs:annotation>
-        <xs:documentation>Used to specify that a URL must be accessed over http or
-        https</xs:documentation>
+        <xs:documentation>Used to specify that a URL must be accessed over http or https, or that
+          there is no preference.</xs:documentation>
       </xs:annotation>
       <xs:simpleType>
         <xs:restriction base="xs:token">
@@ -1042,17 +1042,24 @@
     </xs:attribute>
   </xs:attributeGroup>
   <xs:attributeGroup name="concurrent-sessions.attlist">
-    <xs:attribute name="max-sessions" type="xs:positiveInteger"/>
+    <xs:attribute name="max-sessions" type="xs:positiveInteger">
+      <xs:annotation>
+        <xs:documentation>The maximum number of sessions a single user can have open at the same
+          time. Defaults to "1".</xs:documentation>
+      </xs:annotation>
+    </xs:attribute>
     <xs:attribute name="expired-url" type="xs:string">
       <xs:annotation>
         <xs:documentation>The URL a user will be redirected to if they attempt to use a session
-          which has been "expired" by the concurrent session controller.</xs:documentation>
+          which has been "expired" by the concurrent session controller because they have logged in
+          again.</xs:documentation>
       </xs:annotation>
     </xs:attribute>
     <xs:attribute name="exception-if-maximum-exceeded" type="security:boolean">
       <xs:annotation>
         <xs:documentation>Specifies that an exception should be raised when a user attempts to login
-          twice. The default behaviour is to expire the original session.</xs:documentation>
+          when they already have the maximum configured sessions open. The default behaviour is to
+          expire the original session.</xs:documentation>
       </xs:annotation>
     </xs:attribute>
     <xs:attribute name="session-registry-alias" type="xs:string">
@@ -1152,10 +1159,10 @@
     </xs:complexType>
   </xs:element>
   <xs:attributeGroup name="http-port">
-    <xs:attribute name="http" use="required" type="xs:integer"/>
+    <xs:attribute name="http" use="required" type="xs:string"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="https-port">
-    <xs:attribute name="https" use="required" type="xs:integer"/>
+    <xs:attribute name="https" use="required" type="xs:string"/>
   </xs:attributeGroup>
   <xs:attributeGroup name="x509.attlist">
     <xs:attribute name="subject-principal-regex" type="xs:string">
diff --git a/core/src/test/java/org/springframework/security/config/HttpSecurityBeanDefinitionParserTests.java b/core/src/test/java/org/springframework/security/config/HttpSecurityBeanDefinitionParserTests.java
index 972c8e1cdf..87d2fbdba7 100644
--- a/core/src/test/java/org/springframework/security/config/HttpSecurityBeanDefinitionParserTests.java
+++ b/core/src/test/java/org/springframework/security/config/HttpSecurityBeanDefinitionParserTests.java
@@ -300,6 +300,24 @@ public class HttpSecurityBeanDefinitionParserTests {
         assertEquals(Integer.valueOf(9443), pm.lookupHttpsPort(9080));
     }
 
+    @Test
+    public void portMappingsWorkWithPlaceholders() throws Exception {
+        System.setProperty("http", "9080");
+        System.setProperty("https", "9443");
+        setContext(
+                "    <b:bean id='configurer' class='org.springframework.beans.factory.config.PropertyPlaceholderConfigurer'/>" +
+                "    <http auto-config='true'>" +
+                "        <port-mappings>" +
+                "            <port-mapping http='${http}' https='${https}'/>" +
+                "        </port-mappings>" +
+                "    </http>" + AUTH_PROVIDER_XML);
+
+        PortMapperImpl pm = (PortMapperImpl) appContext.getBean(BeanIds.PORT_MAPPER);
+        assertEquals(1, pm.getTranslatedPortMappings().size());
+        assertEquals(Integer.valueOf(9080), pm.lookupHttpPort(9443));
+        assertEquals(Integer.valueOf(9443), pm.lookupHttpsPort(9080));
+    }
+
     @Test
     public void externalFiltersAreTreatedCorrectly() throws Exception {
         // Decorated user-filters should be added to stack. The others should be ignored.