This doesn't seem correct to me:
<url>/vsphere-client/wicket</url>
It should be
/your-war-Web-ContextPath/wicket
that is something like:
/vsphere-client/your-war-name/wicket
Also make sure that you have the web.xml file configured correctly for the wicket.
I have created a sample with wicket and have posted it in the forum. Go and look for it.