I don't think you can, as the scripts are designed for RMXP's mapping system. This means that it won't be able to load RMVX's maps, unfortunately.
If you've bought RMVX, try using its activation code in XP; I've heard that they use the same activation system, so the code will work in both.
The battle system is already implemented. It can be called with the pbTrainerBattle and pbWildBattle commands (see Notes.html for details).
The Pokémon sprites are added to Graphics/Battlers. The filename consists of the Pokémon's number and the type of sprite (s for shiny, b for back, and sb for both).
Trainers are added to Graphics/Characters. The trainer sprites should be called trainerXXX.png, where XXX is the ID of the trainer type in PBS/Trainernames.txt. The player graphic is added to the same folder; the filename is defined at the top of PBS/Metadata.txt.
You should read the Notes.html file; it contains the answers to all those questions (and more).
I see you are the creator of Pokemon amethyst, it looks awesome! I would like to know when you have the pokemon esentials from poccil, i would like to know somethings
1. How do you make the Pokemon battle system? Where do you insert it?
2. Where do you add all the pokemons front, back?
3. Where would you add the trainers, and main character (front and back)?
:D looking forward for your responce