Modding GBA Doom 2

Well, I was thinking about modding GBA 2... I think it's a interesting version of Doom and a forgotten one to mod.
I've download a program in which you can edit textures, monsters and a lot of stuff in GBA Doom (the first one), but I didn't see that program for Doom II, which is much more complex and attractive to edit.
The program I mean is called 'GBA Doom editor'.
Any suggestion?

Sorry bad English

Sorry for posting again, but I need to know if it's even possible to mod Doom 2 for GBA.
If not, doesn't matter, for Doom 1 it's possible.
The problem is that it seems that Doom 2 uses a different engine... and I found nothing about GBA Doom 2 mods in the internet.

Sorry again.