To add to Fred's comments, as someone who has done a lot of soft x-ray spectroscopy, there is simply not enough "room" above the edge to do EXAFS at these energies.  There is a lot of competition from molecular resonances and other light elements.  For instance, the feature around 290 eV is due to a 1s --> sigma^* transition.  Also, the feature at ~400 eV could as likely originate from some spurious nitrogen in your system than photoelectron scattering.