Hello everyone, I come to inform you that I was able to install FOP2 on a separate server and integrate with the customized Asterisk.
I'll leave the step by step for those who need it:
Note: Special Thanks for the help given by Nicolás Gudiño via chat.
1- I prepared the Ubuntu 18.04 server as follows:
1.1: I installed the prerequisites:
apt update && apt upgrade -y && apt install -y make php php-sqlite3 php-mysql php7.2-xml mariadb-client mariadb-server openssl net-tools dnsutils netcat
2- I edited the file /usr/local/fop2/fop2.cfg informing the data of "AMI definitions" (manager_host, manager_port, manager_user and manager_secret) for the Asterisk server (https://www.fop2.com/docs/installation.php#ConfiguringtheServer)
3- I edited the file /usr/local/fop2/fop2.cfg adding the following line to the end of it: buttonfile=buttons_custom.cfg
4- I edited the file buttonfile=buttons_custom.cfg manually including the buttons for extensions and queues (https://www.fop2.com/docs/installation.php#ConfiguringButtons)
Note: After editing the file buttonfile=buttons_custom.cfg, it is necessary to access the FOP2 admin page and enter the "buttons" menu, so that FOP2 creates in the database the buttons manually added to this file buttonfile=buttons_custom.cfg.
5- Finally, just restart the FOP2 service: systemctl restart fop2
