Vaadin Portal Integration using Maven

Hello everyone,

I'm currently working on Portlet 2.0 support for Vaadin and I have a preliminary implementation the vaadin portlet projet as per the guidence given in the vaadin totorial , the portal project is working fine in the Liferay for the war i exported from the eclipse but my goal is to migrate this project to Maven and do further thing going foward.
so i have converted the project in to maven using eclipse wizard, but after running maven build i'm getting the following error mentioned below ,

[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 21.190s
[INFO] Finished at: Thu Apr 05 15:02:10 IST 2012
[INFO] Final Memory: 5M/38M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-war-plugin:2.1.1:w
ar (default-war) on project myportlet: Error assembling WAR: webxml attribute is
required (or pre-existing WEB-INF/web.xml if executing in update mode) -> [Help
1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e swit
ch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please rea
d the following articles:

and also i have added the plugins in my pom.xml as given below

<plugin> 
                <groupId>org.apache.maven.plugins</groupId> 
                <artifactId>maven-war-plugin</artifactId> 
                <version>2.1.1</version> 
                <configuration> 
                  <!--webappDirectory>/sample/servlet/container/deploy/directory</webappDirectory--> 
                  <packagingExcludes>**/web.xml</packagingExcludes> 
                </configuration> 
            </plugin> 

can any one please guide me how to achive this ...

Thanks in advance
Vasanth

Have you tried the following?

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-war-plugin</artifactId>
  <version>2.5</version>
  <configuration>
    <failOnMissingWebXml>false</failOnMissingWebXml>
  </configuration>
</plugin>