need a little help.

I'm all about customization, I love the plugin FFXIDB but I dislike the circle shape and outline texture of it. I figured the textures were located inside the .dll and basically made my own textures and replaced the bin data in visual studio from the old textures with the ones I've made, but when I tried to load it I just get "file appears to be corrupted".

Is it that we can't edit plugins because they're signed? is there anyone that can help me out? not even sure if its possible to make a LUA for this.

Yes, plugins are signed and can't be modified. You can almost do what you want using primitives from Lua, but they don't support texture offsets, so you would be forced to display the entire map at once.