proxy role is required to check user reference into acl_user

bt5/erp5_configurator/SkinTemplateItem/portal_skins/erp5_configurator/BusinessConfiguration_validateCustomerUsername.xml

@@ -98,6 +98,14 @@ return 1\n
             <key> <string>_params</string> </key>
             <value> <string>editor, REQUEST</string> </value>
         </item>
+        <item>
+            <key> <string>_proxy_roles</string> </key>
+            <value>
+              <tuple>
+                <string>Manager</string>
+	      </tuple>
+	    </value>
+	</item>
         <item>
             <key> <string>id</string> </key>
             <value> <string>BusinessConfiguration_validateCustomerUsername</string> </value>