Results from model II.1, comparing modelling results (left) with the observations (right). From top to bottom PACS 100 μm, PACS 160 μm, SABOCA 350 μm, and LABOCA 870 μm, where intensity units are Jy sr^-1. Including the PAH opacities did not improve the models at the FIR wavelengths, where the models over-predict the intensities observed by Herschel. In contrast, the agreement between models and APEX observations in the submm is very satisfactory, within better than 20%.