Okay, I made tests and they work on mine. Hope can work on yours too.
My case:
I want set my WordPress register page to:
mysitename.com/en/about-us/
Results:
- Better WP Security doesn't block it.
- Register link on Meta Widget works as what I want.
- Register link on login page (wp-login.php) works as what I want.
Here I change this line:
...
RewriteRule ^register/?$ /wp-login.php?blablabla&action=register [R,L]
...Become this:
...
RewriteRule ^register/?$ /en/about-us [R,L]
...Explanation:
The things you need to change are the words: /wp-login.php and blablabla... in this line:
RewriteRule ^register/?$ /wp-login.php?blablabla&action=register [R,L]
To your new link.
It works on my site, hope it works too on yours.