According to this link, WD has enabled TM support.
this further links to which is the official update:
What I could not find is if this relates to the blue rings version. I have followed the steps and cannot finish them. In addition, according to the WD .pdf time machine how-to you can edit settings in the "Network Storage Manager." I can only reach "Shared Storage Manager" which is very confusnig. I am on firmware 2.00.19