For the past few years, manned missions to the ISS take only 6 hours in ascent, all the rendez-vous maneuvering is being done in the duration of 4 orbits.
It used to take a few days, though. However, the crews take a pre-flight enema [0] and go through a diet to avoid having to go #2. There's a story that the Soyuz toilet has been used only once in ISS missions after a Cosmonaut had been eating prunes prior to departure back to earth [sorry, can't find a link].
So for orbital operations to/from the ISS, there's not much use for a space toilet. So little, that I wouldn't be surprised if there's no toilet at all and the fallback plan is to soil your pants, as crude as it sounds.