[Plugin: Private! WordPress Access Control Manager] 'Register' on sub-sites

I have activated the plugin and configured it successfully.Also edited the private.php as instructed .

But when a user clicks on register link/login link on a sub-site, he is still redirecting to his own site .He could access Main site.But what should I do if he need register on sub-site which he wants?

What I need is… if a new User visits a sub-site and want to signin.He should be able to register/login directly on that sub-site.Some plugins like theme-my-login can help with this.But it doesn’t work with multisite installation some times and not at all on buddypress enabled site

Also would you please look at this post and let me know if I can do like something like that?

Thanks !