First u all need to install.. X-prlore n zip manager.. You can find dis somewhers by search engins.. Or i'll post the softwares l8r..
Now lets edit..
1. Create a folder named 'test' in ur mem card..
2. Open a java installation file with X-plore. Eg :- 'mig33beta.jar'
3. Then extract all files to the new folder named 'test'.
4. Now go to that folder and edit 'MANIFEST.MF' (the file in META-INF folder) and change the names as u want..
*MIDlet-name: mig33fire3.7
*MIDlet-1: mig33fire3.7,......
(if u change other texts.. The software myt be crashed)
5. After finish ur editing.. Save the text file and close X-plore.
6. Now open zip man. And create a new archive. mig33fire.zip and add all the files from 'test' folder into da archive. And exit zip man
7. Again open X-plore. Rename the zip file into jar.. (mig33fire.zip ==> mig33fire.jar) now open the .jar file by 'open by system' menu and install
(you can also change the background pic, icons n logo. By ur experience..)
enjoy..!!!