If I'm not mistaken this can only be achieved with a proudct called Adobe
LiveCycle Reader Extensions ES2.
Is there any other option that you are aware of for Mac users?
I have Acrobat 9 pro and want to convert my 100's of PDF files to "comment enabled" PDF files. I am looking for some automation! I looked into rubyPDF, but that solution is only available for windows.
There is no other option, and certainly no other (legal) third-party options.
If you are using an Apple computer you can download an Automator service script that I made. It will enable you to select as many, or as few PDFs as you would like to enable comenting in and will automatically enable each PDF to "enable commenting". You can view the tutorial and download the Automator Script here:
Hope this helps.