How can I get approval for a 4187 for an event hosted by my former unit?

My old unit who hosted the event (a ruck march) sent out the 4187 to the commanders, however it's been 6 months and they haven't seen any results. I'm asking my old NCO to try sending them again, but would my new command be able to sign for the approval? All I have is the certificate from the completion of the event and the badge itself. My old NCO is telling me to route it through my current chain of command and have them sign for it, but my S1 said since they have nothing to do with the event it's not valid. Any advice on what I can do here?