Create the MIDlet project.
Right click on the project and go to 'Properties'.
Go toJ2ME -> Midlet Suite Signing.
In 'Signing Properties', Enable'Sign Project' check-box.
Browse Keystore File
. Provide proper Alias of that keystore file.
Select Password option. You should have key password and keystore password for that Keystore.
Verify the signature using 'Verify Setting'' option. If verification done successfully, it will display message 'The settings verify'
Press OK to complete
Build project to get signed midlet