How can I change tag properties?

I'm working in InDesign Cs6 (MAC 10.7.5) and I have tagged my paragraphs styles (so the PDF will be accessible in Acrobat). I was use to change tag properties directly in Acrobat when needed (for example : "40hrs/week" should be read by the ScreenReader (JAWS, PC)  as "40 HOURS BY week"), so I changed it in the Tags Panel in Acrobat (select the tag, right-clik/Properties/ and I would write "40 HOURS BY week" in Actual Text and Alternate Text Fields). So JAWS read it correctly.

Is it possible to change it directly in InDesign? It would be great

I can't find how, I've tried with "Add attribute", but it doesn't follow in Acrobat....

thanks a lot!