Just include the following link (in your case) wherever you want: https://bkold.dk/asc-net/?authentication=success&action=logout
If you want to modify the redirection when you log out you can do the following. Edit the from line 247 at clean-login.php and you have four ways to modify it.
a) change the url in the last line, but you will lose the control if an user is authenticate or not because the plugin cannot manage external pages.
b) modify each “add_query_arg” by a “wp_safe_redirect” to a custom page depending of the authentication.
c) write me an email to contacto(at)codection.com and I can code for you in your website. Less than an hour.
d) we can update our plugin to include this feature, but as c) means cost. Our time in our company has a value. 2 hours. Price per hour can be detailed by email.
Regards,
Alberto.