AdminReturn: add a new state with the pdf slip return

[SC34]

Hello,

we have an e-store and 1 physical store to sell shoes.

in the RMA function, I added new statuses for which I send a different email if the customer lives near our store or not.
I would like the pdf slip to be available for these 2 differents states: "Waiting for return" (state id2, the default one) and "Waiting for store return" (state id7, the new one that I created).

I modified the AdminReturnController.php file which I placed in the override/controllers/admin folder.
My new email templates are sending well, but the pdf slip is not available on the site for the new id7 status.

I can't find the file that determines the default generation of the pdf for status 2.

Anyone have an idea?
Thank you all,