Using javax.comm from your jar file

I tried all the suggestions for including javax.comm to my jar file but none of them worked.
The problem I kept having was that the jar file I generated would never run for someone who did not have javax.comm installed. The only solution that worked for me was the following:
Maifest file contained the following line:
Class-Path: .\comm.jar

And comm.jar must be present in the same directory as your jar file, i.e. I sent comm.jar along with my jar file and asked users to put both in the same directory.

This worked for java version 1.5.0_09 but did not work for 1.4.x