ppdj

Hi all, I need help in determining the mechanism for the thionation of lactones by P4S10 + hexamethyldisiloxane. The specific paper I am referring to is Curphey, T. J. J. Org. Chem. 2002, 67, 6461-6473. The author there mentions about oxygenating the P4S10 initially, followed by the cleavage of P-O-P units by hexamethyldisiloxane. What I don't understand is how to show this transformation by arrows for something like 7-membered lactone. Any help on this would be greatly appreciated.