Trying to edit skyboxes in Saturn Doom

[Wesker]

As some of you may know, this version has the odd thing of placing Doom II's city skybox in Doom's Inferno Episode levels, as a sort of cheap but incoherent replacement for the animated fire skybox the PlayStation version has for these levels.

So, I was looking into doing a simple fix to this and change the skybox of these levels. The ideal thing would be to import the original Inferno levels skybox, but it's not present in the PlayStation and Sega Saturn versions (replaced by the animated fire skybox, unused in the Sega Saturn version) and maybe it's not that easy to bring it over. So I thought in either placing the reddish Deimos Episode skybox or the also reddish skybox from the final levels of Doom II, which also deem appropiate.

The Sega Saturn version CD has a folder named "SKYS" which seem to store the skyboxes, so I though this would made the task easier. In this folder there's a series of "SKYXX.CHR" and "SKYXX.MAP" files that rank from 01 to 07 and which coincidentally match the number of different skyboxes there are in the game (seven). There's also some "SKY20.CHR SKY20.MAP SKY20.PAL" and "SKY21.CHR SKY21.MAP SKY21.PAL" files present in the same folder. Thinking it would be a simple task of swapping and renaming files, I did some swappig thinking it would change the skyboxes arranging in the game, but the for some reason, nothing changes at all and the game stays pretty much the same despite this.

Before I continue to do more trial and error, I would like to ask if there is someone else who has the Sega Saturn version and possibly understands how the thing go with the skyboxes in this version. I thought it would be a simple fact of messing with the files of the "SKYS" folder but there must be something else. I would be fine with replacing the wrong city skybox in the Inferno levels with any of the more appropiate reddish skyboxes, that's all.

PS: Please, no "Saturn version is crap" thing. I know this version is bad, I just want to do this small mod if possible and that's it.