The biggest problem I had was the light. It was pretty cloudy outside and the sun was just above the house, so not much light was getting in. If I think of it now I wonder why I so desperately wanted the windows to be totally white? The problem when shooting pics like this is that if you are not using any internal light-source, the windows burn the image with their whiteness and the contour of the objects gets very very soft; so if you don't specially desire that, avoid it.
The light settings: to my disposal I had a big soft-box, a big reflective panel and a on-camera flash. So I placed the soft-box lightning from right to left. And on the left I've placed that big reflective panel. For additional top-light I used the on-camera flash facing upwards.
This way I obtained nice light for the models, but the corner in the back is very dark. If I think of it now, I should have faced the soft-box to that wall between the windows, and the reflecting panel besides me, shining on the model... it would probably have worked better.
Because of the pretty bad light conditions I had to shoot at f3.5 average (which was not so bad) but speeds of 1/20, 1/30 which is very slow, so I used the tripod for all shots.
Conclusion: if you don't have any competitive lighting solutions, don't start shooting inside on a clouded day.