The carrier name is not normally used in themes because it uses up valuable realestate and most know which carrier they are on. If you decide to add it you must just check mark the box in the Plazmic Theme maker.
As for the simulator it should show the name "Fledge Network" if you have done that correctly. The second way to test is to load the theme on your phone. I suggest loading it view SD/OTA so that you phone does not have to reset.
To do this you export as a Jad file. Then move the jad and all cods to you SD card. Navigate to the SD card and select the jad file and you will install the theme via OTA without needing the internet.