From your previous posts on the forum it seems that you are using Cuety-LPU1.
Sadly Cuety cannot manage fixtures with sub-fixtures (pixel individual control). The 12 and 16ch modes of your fixture are using subfixtures to control each light individually, this is why they are not showing up in the cuety library.
Anyway there is a turn around, using the Vbuilder software you can create one fixture for the main control and then use a single channel generic dimmer fixture for each LED. Patching the main control fixture at your fixture DMX address and then 8 single channel dimmer fixture from dmx address +4 you will end up with 9 fixtures in cuety that will allow you to use the 12ch mode.
I hope this will help you,
Enjoy
