Masking URL on Membership doesn't work

I asked this question elsewhere but didn't get an answer that works for me. Perhaps I don't understand the function of masking a URL in Membership. My assumption has been that one could take a folder of downloads that are already on the site and mask their real location on the download link through Membership.

But what I don't understand is whether all these files have to be uploaded via the WP uploader. This doesn't make sense to me, especially since some of these files may be very large, and they may not be able to be uploaded via Wordpress. If that is the case, then perhaps another Membership function would do what I want to do. Please advise how I should proceed to achieve the functionality I desire.

Please excuse the double posting, but my question hasn't been answered in a way that is useful to me. The documentation seems to leave out essential information and I have searched for a week already for this answer.

----------
I am setting up my membership site so that different memberships have bonus ebook rewards for signing up. They would be able to access a page with all the ebook formats upon registering for a plan; the link to this page would be available on the "welcome" page that they are routed to after paying. I will be hiding each bonus link under a shortcode for that memebership plan, but am leaving a sample link open now for you to test.

Website testing page:http://www.parallelmindzz.com/welcome

Try to access the page for the book. I want the registered members to be able to access this main page so they can choose the ebook format that is best for them and download the book. Of course, the page, "testdownload.html" should be masked as well as the download links.

How to get the Masking feature to work at all. Using the default original URL of:
http://www.parallelmindzz.com/wp-content/uploads/

Set the masked URL to:
http://www.parallelmindzz.com/members-content

Set protected groups to:
default

I have only two access levels:

1. Visitors (which are strangers with no subscription or membership)
2. Members (which are paying members)

Download group settings:?Visitors: negative rules for all download groups

Members: positive rules for all download groups

Neither setting works! Whether in the negative or the positive, whether a visitor or a member, you can still see the real URL as listed above.

You can check the link as a visitor or as a test member:

Member: iPhone
Password: i

---------

I am trying to mask the download URL of my PDF books. I understand now that the default WP uploads folder cannot be changed, but I cannot get the masking function to work as described in the manual. Regardless of whether you are logged in as the test member iPhone (see my question above), or not logged in at all, the real URL is showing. (I am testing it by logging out as Admin)

According to the manual there are 3 ways to protect the URLs of downloadable media:

1. Masking the URL (my preferred method)

2. Protecting the media at the time of uploading the file (this is not optimal for me, as the files are already uploaded)

3. Protecting the URL group.

------
Below is the masked Downloads section of the manual:

Downloads / Media
The Membership plugin is one of the only membership plugins for WordPress which allows you to protect your media uploads. You can even mask a specific URL to prevent direct access. This is great for downloads like PDF eBooks, JPEG files, MP3 files, Flash video files, source code files or perhaps your own WordPress plugins and themes.

Figure 2.16 shows a sample of the settings under the “downloads media” tab. You’ll notice that there are three options for protecting media uploads:

13. Basic - Masks your media directory but leaves any filenames the same.

14. Complete - Masks the media directory and changes the image filename as well.

15. Hybrid – This is for use if you are using a host or server that has a problem with the system (such as some installs of nginx). Check with your hosting provider to see if this method may be required for your site.

Figure 2.16
Membership 3.0 Documentation Page 27 Of 79
After the three protection options, you’ll notice the URL where your protected media uploads will be located. Below that, you’ll have a place to input the URL which your users will see in their browser in place of the true URL where your media is located. For example, if your media uploads are located in this directory...

http://www.yoursite.com/wp-content/uploads/

...and you choose this as the masked URL...

http://www.yoursite.com/stayout

...the above URL is all your users will see when they access any of the content under this directory:

http://www.yoursite.com/wp-content/uploads/

--------

My Welcome page's link to The Way of Love book remains the original unmasked version no matter what I do.