hi,
Do you use the last version of cuety (V1.03)? If yes you should be able to find a "PAR 64 Short 18x3w" fixture in the showtec manufacturer list.
If you do not find it, you can use the personality file i join with this mail to add it.
If this is not the fixture you are requesting, you can use the builder software to create your own, or if you give me a link to the manual i can create it for you.