Update ItemsAdder to 3.3.0+
Create a new folder: ItemsAdder/contents/space/resourcepack/
ItemsAdder/contents/space/resourcepack/
Extract the Space plugin resourcepack in the previous folder so that you have something like that: ItemsAdder/contents/space/resourcepack/assets/...
ItemsAdder/contents/space/resourcepack/assets/...
Then run /iazip and follow the hosting tutorial.
/iazip
After you've merged the resourcepacks you will notice double particles from blocks. This is normal and I can't fix it for now, it's because of how Space plugin creases blocks models (in the wrong way).