As it currently stands (v0.9.615.1), you cannot create our solar system. The maximum orbit distance is capped at 1,000 Gm, which gets you part way from Jupiter to Saturn, meaning you can't place Saturn, Uranus, Neptune, or the more distant dwarf planets, at their correct orbits. I can understand having a reasonable size limit in the system creator, but seeing as the same exact orbit calculations would be used literally no matter how far you placed them, it would be a really, really nice touch to be able to create our own solar system yourself from scratch, with all the real-life bodies you decided to include. I don't know if the 1,000 Gm limit is tied to the fact that the orbit distance can only be set via slider and not by manually typing in a number like you can with all the other orbit options, but that really shouldn't be the deciding factor for this sort of core feature. Not to mention that you should absolutely be able to type it in anyway, but that's a different suggestion altogether.
@Exo200 That may be, but I and probably most people don't know how to do that and would have to find a forum post about it (e.g., this conversation), rather than it being a very simple feature to implement. It's literally about changing one number - the maximum orbit distance. All the necessary equations are already there.