I'm gonna post this for posterity, hopefully it will help others.
You need to create an appinstaller file
It will look more or less like this:
(yeah, this "great" forum ignores anything with "<" and ">" and it's so smart, that it won't allow me to attach it - first, because of the wrong extension, and then when I renamed it as xml, it told me that it's invalid. Awesome work Microsoft!)
You can simply get it here: https://phot-awe.com/resources/test.installer - I've tweaked it a bit so you know what you need to replace.