I did that long ago. When people click on Login in the comment section of a post, they are directed to the login page I create. Again: this is a Wordpress page. What next? How how to make the connection with WPdiscuz in Wordpress? Magic? Css?
In the case of the wpForo login page, once you click on the "Sign In" button it'll be redirected to the same page, where the login button is being clicked.
The redirection should be provided by your login/registration plugin. wpDiscuz doesn't have any relation with it.
In case you want to say thank you! 🙂 We'd really appreciate if you leave a good review on the plugin page. This is the best way to say thank you to this project and the support team.