We are developing a tool, iBioSim, which may have some of the functionality that you are looking for. We have support for developing Petri net models which are then saved as SBML using our model editor. Essentially, places are specially annotated parameters while transitions are specially annotated events. We can also translate these SBML models of Petri nets into a Petri net file format though it is one of our own design and not a standard. It does not, however, translate an arbitrary SBML file into a Petri net. We could likely add such support, but I'm not entirely sure what the resulting model could be used for. Namely, it would encode each species as a place and reaction as a transition, but it would be an infinite state (or very large) system in most practical cases. We do, however, have a method that translates our genetic circuit models expressed in SBML into a finite state stochastic Petri net through a series of abstractions (see Madsen et al, CIBCB 2012).
If I knew more about the purpose of your translation, I could perhaps provide a better answer.