@Command: girls not working is more of a bug than a difficulty thing, but regardless, there are a few tricks to get around the problem. The main thing is to lower their rebellion; I've found that any value lower than about -40 will let them work on a pretty routine basis, and once they do than then they'll start working more and more often as they start enjoying it. The thing to do, then, is to get that rebellion level to the magic -40, or if you're in a hurry, at least -20.
There are a couple ways to do that, depending on how you like to play and what you consider exploits. The simplist way is just to buy girls with already low values - this tends to limit you to randoms, though, so if you're like me you'll tend to do this only at the start of the game when you need the steady income. Once you have some money coming in, your options expand a bit: you pretty much can do three things.
First, and perhaps easiest, is to send every girl to the dungeon. For most girls without any "aggressive" traits, a month or so in lockdown with torture should get your rebellion low enough. It's harder to do on the tougher girls, but if you keep them alive and keep working on them, they'll cave sooner or later.
The second choice is to use items. The issue here is that the default items that come with the game aren't really good for this; you'll either have to create your own or find a mod. Currently, the only real item mod is sgb's, which is very decent and has some things that will make lowering rebellion almost trivial given enough money (and, in some cases, time). sgb also did a good job of not making his items feel like exploits, or overpowered - I'd recommend getting his mod regardless of which option you prefer.
The last, and probably toughest, way is to communicate. You have a "Talk to..." button: use it! Chatting slowly makes girls like you more, and once you get them to love you, start asking them to do the other acts. Their rebellion will slowly sink, but more importantly they'll start to enjoy the acts. This method is debatably the most time-consuming, but for the real hard cases it can sometimes actually be quicker than waiting for the girl's will to break. A note, here: use "Scold" sparingly. Even for the more meek girls, it only helps for a while, then it actually starts to raise rebellion. I prefer chatting (not about anything specific). Just remember that even if the rebellion stat isn't visibly lowering, the love stat is rising, and that's the one you're working on with this method.