You can't use VSIX to install CR_Documentor because the installer metadata doesn't include VS11 as supported.

The VSIX has been updated to allow installation into VS11, but DXCore isn't picking VSIX-installed extensions up. http://www.devexpress.com/Support/Center/p/Q399316.aspx

I'll probably wait until that's resolved before releasing the updated version so people aren't confused as to why it's showing up.