Well, I've found the answer myself:
Just create a file (like fakecron.php) and, after the right code to start whenever you want, put this:
$command = "cd /var/www/vhosts/WWW.YOURWEBSITE.COM/httpdocs/generator/; php -q runcrawl.php";
$test = shell_exec($command);
(works on linux with safe_mode off)
Obviously there's more code to add, but a normal php programmer can do it by himself.