Through trial and error, I figured out that the maps are located in data/maps/... and the name we use is the one found through a search in text.pak.
I took the Agrael's Trial map, and everything worked as expected, almost. It can be edited and started. (A2S4)
But War of the Worlds: XL1 no longer works.
I packed it in .zip format using WinRAR and renamed the extension to .h5m.
Please tell me specifically where I went wrong, using XL1 as an example.