Adobe Reader 6.01 continues to work for me in CX Office 4.0. I repeated the previously mentioned install procedures.
When installing an unsupported application, change the 'Windows version for this application' to 'Windows Millenium'. Complete the install. Open your favorite text editor, point it at ~/.cxoffice/dotwine/config and add
[AppDefaults\\AcroRd32.exe\\Version]
"Windows" = "win2k"
This was tested on Adobe 6.0.1. The icons are still messed up, but otherwise appears to handle basic PDF opening and viewing without issue.