Bind JNDI datasource in tomcat?

Is it possible to bind programatically a DataSource to Tomcat's 6 JNDI?

I want to create a DataSource on the fly and then make it available through JNDI ( to ColdFusion for instance ).

This is what I have:

public void bindToConext(DataSource dataSource) throws NamingException, SQLException {
    Context initContext = new InitialContext();
    Context envContext  = (Context)initContext.lookup("java:/comp/env");
    envContext.bind("jdbc/mydatasource", dataSource);
}

But I'm getting this exception:

javax.naming.OperationNotSupportedException: Context is read only

Is there a work around?