Configuration for Strongswan


Im trying to configure strongswan but is missing a little bit some more configuration.
That my nix configuration :

services.strongswan.secrets = [ "/etc/ipsec.d/ipsec.secrets" ]; = "add";
  services.strongswan.connections.vpn.keyexchange = "ikev1";
  services.strongswan.connections.vpn.left = "%any";
  services.strongswan.connections.vpn.leftsourceip = "%config";
  services.strongswan.connections.vpn.leftdns = "";
  services.strongswan.connections.vpn.leftid = "me";
  services.strongswan.connections.vpn.authby = "rsasig";
  services.strongswan.connections.vpn.leftcert = "me.crt.pem";
  services.strongswan.connections.vpn.leftfirewall = "no";
  services.strongswan.connections.vpn.right = "";
  services.strongswan.connections.vpn.rightid = "%any";
  services.strongswan.connections.vpn.rightsubnet = "";
  services.strongswan.connections.vpn.esp = "aes256-sha256-modp2048";
  services.strongswan.connections.vpn.ike = "aes256-sha256-modp2048";
  services.strongswan.connections.vpn.ikelifetime = "360m";
  services.strongswan.connections.vpn.lifetime = "60m";
  services.strongswan.connections.subconn.fragmentation = "yes";
  services.strongswan.enable = true;

That is my cert/key install :

sudo cp ./CA.crt /etc/ipsec.d/cacerts/VPN.crt
sudo cp ./me.crt.pem /etc/ipsec.d/certs/me.crt.pem
sudo cp ./me.key.pem /etc/ipsec.d/private/me.key.pem
sudo echo ": PKCS8 "me.key.pem" xxxxxxxxx=" > /etc/ipsec.secrets
sudo chmod 600 /etc/ipsec.d/private/me.key.pem
sudo chown -R root /etc/ipsec.{conf,secrets,d/}

when try to connect with sudo ipsec up vpn

initiating Main Mode IKE_SA mcif[1] to
no private key found for 'me'
configuration uses unsupported authentication
establishing connection 'vpn' failed

with systemctl status strongswan i see :

opening '/nix/store/609srwzakbrhh8kyyqj2v0hc0f30dv9b-strongswan-5.9.10/etc/ipsec.d/certs/me.crt.pem' failed: No such file or directory
Also this folder is read-only proably need to set where is me.crt.pem & me.key.pem
But i don’t know how to do that.

Best Regards