pdf relations with custom modules

Hi

I’ve created a custom module with relations to the Account and the Contacts tables.
i have added this custom module to the pdf template dropdown and it seems to work properly (The type dropdown).

Now, i would like to insert my contact and account informations into the pdf template but the 2 “Insert field” dropdowns are blank so i’m unable to create links to the informations i need in those tables

Do you have a fix for this ?

Have a nice day

Multicrm