I'm not going to watch the video, but the problem is the ciosmaps.xml. This file tells your installer what cios it can install. You can't scroll to the cios that you want because the installer doesn't have it included in its map.
Each cios comes with its own xml file (e.g. d2x-v10-beta53-alt will have a ciosmaps.xml included in the zip file). When I hacked my wii I just swapped out the ciosmaps.xml for each cios as I installed them. It's a bit tedious, but it's an easy way to make sure your ciosmaps.xml always includes the cios you want to install.
So for instance I
I downloaded d2x-v10-beta52
I extracted it to the sd card with its ciosmaps.xml
I installed it to slot 249
Then
I downloaded d2x-v10-beta53alt
I extracted it to the sd card with its ciosmaps.xml
I installed it to slot 250
Sorry I don't have a better fix, but this will work.