Thanks for the query. From what we infer, you wish FreeRTOS+TCP stack to have a function for users to manually add a static ARP table.
This is a feature, which has not been added yet. Can you please add this as a Feature Request here and then we can have a look?
It would also be very helpful for the forum, if you can post your question in English
Furthermore, if you’ve already implented your solution, it’s always welcome to create a pull request to the corresponding repository.