You don't have to create an empty DAT file, SC4Tool will create one itself by clicking on the "star" icon. And even if it's only a small personal texture set, you should get an ID range, as the default range that is supplied in SC4Tool might collide with some other textures. As Biriali said, those textures look like overlay textures or network (traffic) textures, so they would need an alpha map. Also, make sure to select the proper IDs in order to avoid wealth-dependent conflicts (you can read more about texture IDs in the various texture tutorials here at SC4D).