Thumbnails not showing up in CMS if PREFIX_URL is set

I'm building a site for a client and incorporating a few slideshows. Each slideshow has its own image directory; the images being uploaded through the CMS. The client has a site already, but we're going to be switching servers when the new site is done. So I'm working on a server by accessing it using the IP address / ~client format: ex: http://111.222.333.44/~client

In CMS builder, under General Settings, I set a Website Prefix URL of /~client.

When I set up the slideshow table I created an upload field called 'slides' and set a custom upload directory. I also set the List Page Fields to: title, slides -- so that I can see the thumbnail of the image in the listing within the CMS. The problem is that the thumbnails are not showing up. It looks like the PREFIX_URL is not being added to the img src, so I'm getting a broken URL. The slideshow, however, works perfectly in the website.

I've tried a lot of different settings combinations and nothing seems to work. For example, I can get the thumbnails to show in the CMS, but then the slideshow breaks in the website.

By the way, I do not have this problem when the site is installed on a server without a PREFIX_URL. Everything works fine then.

Either I'm doing something wrong, or else one of the CMS files needs to be edited to add a missing PREFIX_URL constant. Could use your help.

Hope I was somewhat clear about the problem. If not, let me know and I'll give you a call.

Thanks.

Jim