form tag structure in Acrobat 8

Hi,
I'm trying to find out best practice accessibility form tag structure in Acrobat 8 professional. When you run form field recognition on a word based PDF that already has form 'areas', Acrobat will place a form tag around the area. When you insert a form field manually from the forms toolbar (with highlight properties and tag annotations options on) it does not generate a form tag around the element. I'm trying to find out what the tag structure should be. Can you please tell me if all form elements need to be inside a form tag, i.e. I will manually have to insert additional form tags in the tag panel for each object, or is the way that the form toolbar inserts the form field as an object enough?

Thanks,
Megs4455