diff --git a/schema/lib/types/std.xsd b/schema/lib/types/std.xsd
index cc07cdd..78d3d49 100644
--- a/schema/lib/types/std.xsd
+++ b/schema/lib/types/std.xsd
@@ -9,14 +9,12 @@
             <xs:whiteSpace value="collapse"/>
         </xs:restriction>
     </xs:simpleType>
-    
-    <xs:complexType name="t_std_base64">
-        <xs:simpleContent>
-            <xs:restriction base="xs:token">
-                <xs:pattern value="[A-Za-z0-9+/=]+"/>
-            </xs:restriction>
-        </xs:simpleContent>
-    </xs:complexType>
+
+    <xs:simpleType name="t_std_base64">
+        <xs:restriction base="xs:token">
+            <xs:pattern value="[A-Za-z0-9+/=]+"/>
+        </xs:restriction>
+    </xs:simpleType>
 
     <xs:complexType name="t_std_cmdopts">
         <xs:simpleContent>