diff --git a/ganttzk/pom.xml b/ganttzk/pom.xml
index cc30e4f1b..aa58a6a84 100644
--- a/ganttzk/pom.xml
+++ b/ganttzk/pom.xml
@@ -103,6 +103,10 @@
             <groupId>jfree</groupId>
             <artifactId>jfreechart-igalia</artifactId>
         </dependency>
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>servlet-api</artifactId>
+        </dependency>
     </dependencies>
 
 </project>
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/servlets/CallbackServlet.java b/ganttzk/src/main/java/org/zkoss/ganttz/servlets/CallbackServlet.java
similarity index 98%
rename from navalplanner-webapp/src/main/java/org/navalplanner/web/servlets/CallbackServlet.java
rename to ganttzk/src/main/java/org/zkoss/ganttz/servlets/CallbackServlet.java
index 7d392f61e..cc39edbc6 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/servlets/CallbackServlet.java
+++ b/ganttzk/src/main/java/org/zkoss/ganttz/servlets/CallbackServlet.java
@@ -17,7 +17,7 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package org.navalplanner.web.servlets;
+package org.zkoss.ganttz.servlets;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -31,11 +31,11 @@ import java.util.concurrent.ConcurrentMap;
 
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
-import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.apache.commons.lang.Validate;
+import org.zkoss.web.servlet.http.HttpServlet;
 
 /**
  * Servlet that allows to register custom responses. It must be declared at
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/chart/ChartFiller.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/chart/ChartFiller.java
index 240c1d22b..dc65676b6 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/chart/ChartFiller.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/chart/ChartFiller.java
@@ -45,8 +45,6 @@ import org.navalplanner.business.calendars.entities.ResourceCalendar;
 import org.navalplanner.business.calendars.entities.SameWorkHoursEveryDay;
 import org.navalplanner.business.planner.entities.DayAssignment;
 import org.navalplanner.business.resources.entities.Resource;
-import org.navalplanner.web.servlets.CallbackServlet;
-import org.navalplanner.web.servlets.CallbackServlet.IServletRequestHandler;
 import org.zkforge.timeplot.Plotinfo;
 import org.zkforge.timeplot.Timeplot;
 import org.zkforge.timeplot.data.PlotDataSource;
@@ -54,6 +52,8 @@ import org.zkforge.timeplot.geometry.DefaultTimeGeometry;
 import org.zkforge.timeplot.geometry.DefaultValueGeometry;
 import org.zkforge.timeplot.geometry.TimeGeometry;
 import org.zkforge.timeplot.geometry.ValueGeometry;
+import org.zkoss.ganttz.servlets.CallbackServlet;
+import org.zkoss.ganttz.servlets.CallbackServlet.IServletRequestHandler;
 import org.zkoss.ganttz.timetracker.zoom.ZoomLevel;
 import org.zkoss.ganttz.util.Interval;
 import org.zkoss.zk.ui.Executions;
diff --git a/navalplanner-webapp/src/main/webapp/WEB-INF/web.xml b/navalplanner-webapp/src/main/webapp/WEB-INF/web.xml
index 90773ac82..ffd28966c 100644
--- a/navalplanner-webapp/src/main/webapp/WEB-INF/web.xml
+++ b/navalplanner-webapp/src/main/webapp/WEB-INF/web.xml
@@ -33,7 +33,7 @@
     <servlet>
         <description><![CDATA[Callback Servlet]]></description>
         <servlet-name>callbackServlet</servlet-name>
-        <servlet-class>org.navalplanner.web.servlets.CallbackServlet</servlet-class>
+        <servlet-class>org.zkoss.ganttz.servlets.CallbackServlet</servlet-class>
         <load-on-startup>1</load-on-startup>
     </servlet>
     <servlet-mapping>