Flex development - no server app change to j2ee app - RemoteObject faultDetail=null

If you created a flex app with no server technology and you want to change that to j2ee app.
or your RemoteObject always fault and faultDetail=null

•  Try to modify your flex compiler arguments .

            Add -services "somewhere on your computer/WEB-INF/flex/services-config.xml"

•  Find .flexProperties file and add 

            serverContextRoot="/????"
            serverRoot="????"
           serverRootURL="http://????"
           ???? depend on your j2ee server settings