diff --git a/spring-integration-gemfire/src/main/resources/org/springframework/integration/gemfire/config/xml/spring-integration-gemfire-4.0.xsd b/spring-integration-gemfire/src/main/resources/org/springframework/integration/gemfire/config/xml/spring-integration-gemfire-4.0.xsd
index 38511a77b7..e09f207d0d 100644
--- a/spring-integration-gemfire/src/main/resources/org/springframework/integration/gemfire/config/xml/spring-integration-gemfire-4.0.xsd
+++ b/spring-integration-gemfire/src/main/resources/org/springframework/integration/gemfire/config/xml/spring-integration-gemfire-4.0.xsd
@@ -205,7 +205,8 @@
 		<xsd:attribute name="expression" type="xsd:string" use="optional">
 			<xsd:annotation>
 				<xsd:documentation><![CDATA[
-					Expression to be evaluated to produce a value for the payload.
+					Expression to be evaluated to produce a value for the payload. The root object of the
+					expression evaluation is the GemFire 'EntryEvent'.
 				]]></xsd:documentation>
 			</xsd:annotation>
 		</xsd:attribute>
diff --git a/src/reference/docbook/gemfire.xml b/src/reference/docbook/gemfire.xml
index 5594c29c48..76883726e9 100644
--- a/src/reference/docbook/gemfire.xml
+++ b/src/reference/docbook/gemfire.xml
@@ -46,7 +46,12 @@ xsi:schemaLocation="http://www.springframework.org/schema/integration/gemfire
 	which can contain a comma separated list of event types for which a message will be produced on the input channel. By default CREATED and UPDATED are enabled.
 	Note that this adapter conforms to Spring integration conventions.
 	If no <code>channel</code> attribute is provided, the channel will be created from the <code>id</code> attribute. This adapter also supports an <code>error-channel</code>.
-	If <code>expression</code> is not provided the message payload will be a GemFire <classname>EntryEvent</classname>
+	The GemFire <ulink url=
+	"http://www.gemstone.com/docs/current/product/docs/japi/com/gemstone/gemfire/cache/EntryEvent.html">EntryEvent</ulink>
+	is the <code>#root</code> object of the <code>expression</code> evaluation.
+	Example:<programlisting><![CDATA[expression="new foo.MyEvent(key, oldValue, newValue)"]]></programlisting>
+	If the <code>expression</code> attribute is not provided, the message payload will be the GemFire
+	<classname>EntryEvent</classname> itself.
   	</para>
   </section>
    <section id="gemfire-cq">