In order to see the Custom Media Type in your print program -
PC: You need to update your media information - Follow this video https://www.youtube.com/watch?v=QFYVuBOxl2w&index=10&list=PL7Ndp_jw_jSnCpGRxVUXR2iaeFbblRqOP
MAC: You need to run a media information update - https://youtu.be/zt3JAcWgS98