You include those three jar files in the outer file exactly the way you did it. That part works fine. But then there is no way to declare the classpath so that it includes those three jar files, so it is pointless to do so.
>How can I include mail.jar activation.jar and soap.jar in this new jar file?
You can't. There is no provision for the java command to look for jar files inside of another jar file. All the jar files MUST be as separate files in some folder. See the Class-path: entry in the manifest as one possiblity. Or use a full commandline: java -classpath <all the jars> <program>