How can I see the comments in PDF document on Chrome OS?

Hi, I am trying to view the comments in a PDF document on my Chromebook (Chrome OS). The PDF viewer in Chrome cannot show them (I see only the graphical hints, like yellow background and such). I tried several apps in the Chrome store, but none of them could show the comments in the PDF document. There is an app to comment a PDF file, but it uses a proprietary format, and is incompatible with the comments created by Adobe Acrobat. I also tried to upload the PDF to the Acrobat.com webspace. While it provides an online viewer, even the Acrobat.com webspace viewer does not show the comments . So I am running out of ideas, and still cannot see the comments of the PDF on my Chromebook...

Is there something obvious I am missing? Is there an app that can show comments on Chromebooks?

Thank you!

Claus