As the subject states, can you select custom liveries for built in scenarios? I have successfully gotten some to show up when I select them through timetable menu.
No you cannot....only in timetable mode. Hopefully additonal functionality such as this will come with Livery Designer 2.0 which is currently sitting as in planning on the roadmap
All a bit random at the minute. Custom liveries were consistent and available to use in scenario and timetable mode, but since the eastcoastway livery function becoming available early this year, its now anyones guess what can and cant be used.