I am unsure exactly what you want to do based on the discussion…
If you want to:
a) change the login url of wp from http://yoursite.com/wp-login.php to something else, ie http://yoursite.com/mylogin
and
b) then have simple press login button redirect to that login page
that is pretty simple and straight forward…
1) install the theme my login plugin (https://wordpress.org/plugins/theme-my-login/) which allows you to set up your login page as you want…
2) update the sp_LogInOutButton template tag (see https://simple-press.com/documentation/codex/api/template-functions-and-the-api/display-template-functions/common-view/sp_loginoutbutton/) in your sp theme, from (based on default theme):
sp_LogInOutButton('tagClass=spButton spRight', __sp('Log In'), __sp('Log Out'), __sp('Log in and log out'));
to
sp_LogInOutButton('tagClass=spButton spRight&logInLink=http://yoursite.com/mylogin', __sp('Log In'), __sp('Log Out'), __sp('Log in and log out'));
the change being adding:
&logInLink=http://yoursite.com/mylogin
so give it a shot… If you still would like us to do it, we could do the work for $25…