1) Choose the application you want to move to another category.
2) FTP your PS3.
3) Locate to your chosen application folder
4) Copy the PARAM.SFO in the desktop.Before you edit it make a backup of the PARAM.SFO first.
5) Use a HEX editor and search for the HG, it's 99% the same for all the homebrew applications expect the Red Dragon which has the CB.
Also you can use a SFO editor.
6) Change it to any of this:
HM --> Playstation Network
CB --> Network
HG --> Game
AV --> Video
AM --> Music
AP --> Photo
AT --> TV
For example i will move the Showtime to Video category.
The location for the Showtime is is the red circle.
I copied it to my PC and then i opened it with a SFO editor.
I changed the HG (in the red circle)
I saved it and i replaced it with one from the /dev_hdd0/game/THSS00003/ folder.
After that i ran the application and after the exit it moved into it's new location.