How to write on a PDF document using stylus in a TAB ?

Hi,

I have a DELL VENUE PRO 11 TAB with a Stylus. I am trying to write some text (as my notes) on a PDF document using Adobe Reader 8.1 & Adobe Acrobat 11, but it's not working.

Can you help me to understand the right procedure of doing this. I just want to use my Stylus to write something on a PDF Page using your applications.

Thank you.

Raju