Hi Fernando,
your Blender doesn’t work inverse, but the naming is just a bit confusing. If you have Vertex Group enabled it works:

And if you have it disabled, you get mirroring of the mesh, like this:

So you could say, it mirrors the Vertex Group now and not in the first example, but meant is, that if the Vertex Group option is enabled, blender mirrors the Vertex Group to the mirrored Bone.