I created a pdf form in Acrobat Pro 10 and saved using the extended Reader using the Enable Additional Features. When I access the pdf online, I can add a digital signature, I can fill in all the text and form fields, I can email it, save it etc. However, if I click on the Sign button, I can't sign it that way (ie the non-digital signature way).
When I click on the button I get the same security message that I did before I had saved it using the extended reader enabled (security settings on this document prevent adding text and/or placing a signature on it). I CAN add text and add a digital signature though.
This is SO annoying.
Somewhere else I was told that Acrobat 9 Standard does not allow this functionality but Acrobat 9 Professional does. I haven't been able to test it myself.
I do not understand which "Sign" button are you talking about? When you say "add a digital signature", do you mean signing the document or adding an unsigned signature field for future signing? Please, provide more details.
If a PDF is reader-enabled it can be used in any Adobe PDF Viewer: Reader, Standard, Pro.