Add author to pdf

I produce a quarterly bulletin, which I publish as a pdf. This is written in Pages 4.3 and exported. Previous issues on OS X 10.8 have my name as Author. Recent issues on OS X 10.9 show unknown author.

How can I change this on new exports?

Doesn't fix your export problem, but this is a fairly easy workaround. You can easily edit PDF metadata using a very simple automator workflow:

1. Open Automator and create a new Service
2. Set 'Service receives selected' to PDF files 'in' Finder.app
3. Search for 'set meta' and drag and drop the Set PDF Metadata action to the right
4. At the bottom under 'Options' select Show this action when workflow runs
5. Save the service and give it a name
6. Optionally, create a keyboard shortcut under System Preferences > Keyboard > Shortcuts, select 'Services' from the left pane and look for your service under 'Files and Folders'

Now you can right click a PDF file and under services select your service, or select a PDF file and use your newly created shortcut to launch your Service.

Hope this helps.