Okay, found out how to do it myself:
shader = Content.Load<Effect>("Shader.tkfxo");
is my shader.
When I was debugging, I found the Parameters
property of the effect. I've found that the index at 2
was corresponding to a Texture2D
object. It was looking for an array so I used shader.Parameters[2].SetResource<Texture2D>(new Texture2D[] { myTextureObject });
and it worked flawlessly.