[feature] Request for Auto-Unseal Feature Implementation

I need to unseal the vault using an external vault.
I'm trying to auto-unsealed with another Vault using the method described here https://developer.hashicorp.com/vault/tutorials/auto-unseal/autounseal-transit
However, I'm encountering an issue where it's not possible to modify the default configuration of the vault at the location "/var/snap/vault/common/vault.hcl" in order to enable autounseal

My steps:

On the external vault:
vault secrets enable transit
vault write -f transit/keys/autounseal
tee autounseal.hcl <<EOF
path "transit/encrypt/autounseal" {
   capabilities = [ "update" ]
}

path "transit/decrypt/autounseal" {
   capabilities = [ "update" ]
}
EOF
vault policy write autounseal autounseal.hcl
vault token create -orphan -policy="autounseal" -wrap-ttl=120 -period=24h

On the charm vault:

VAULT_TOKEN=<wrapping_token> vault unwrap

then I should add in /var/snap/vault/common/vault.hcl

seal "transit" {
  address = "http://<external-vault-ip>:8200"
  disable_renewal = "false"
  key_name = "autounseal"
  mount_path = "transit/"
  tls_skip_verify = "true"
}

At the moment I can't find another way to use an external vault to unseal the key in the internal vault.