Adobe Contribute 6.5 not working with Explicit FTP over TLS

We are concatenating multiple web servers running SLES 10 or SLES 11 to a WHM/Cpanel host.

Previously, ftp administration was a mysql backend to pure-ftpd with zero documentation.

Contribute users were setup with connection keys, and administrative passwords misplaced, so new connection keys have to be made.

We are an Education Service District, and support a dozen school districts, and host websites for 9 of them.

Creating new connection keys to use with Contribute 6.5 do not work with Explicit FTP over TLS. FTP clients work. The administrative user works in Contribute, but the delegated Contribute users in Connection Keys do not work at all using ftps. Mod_Security is turned off because all the sites we are migrating have custom php 404 and 403 pages.

I do not see any errors or any other logging information to give me any clues as to why this isn't working. I tried turning cphulk off, no effect.

Any ideas? Server has a properly chained SSL certificate, am I going to need an SSL certificate per hosted domain?