unable to lookup an EJB from a JavaBean

[Hussein Baghdadi]

Hi all.
I'm creating a J2EE application.
my web application contains a simple JavaBean that hides the operation of locating my Session EJB.

Object obj = ic.lookup("java:comp/env/ejb/Liga");
LigaHome home = (LigaHome)PortableRemoteObject.narrow(obj, LigaHome.class);

this JavaBean will be used by servlets, JSPs.
this is the important part of jboss.xml :
<session>
<ejb-name>LigaBean</ejb-bean>
<jndi-name>ejb/Liga</jndi>
</session>
when trying to use the application, I got the exception :
javax.naming.NameNotFoundException: ejb not bound
I changed <jndi-element> to Liga , I got the same exception
the application is only works if I do the following :
Object obj = ic.lookup("Liga");
any ideas ???
thanks.