Save edited forms in Acrobat Reader versions lower then XI

I bought PDF Architect 2 Pro to create forms that users can fill/edit and save. But Architect only can do this with Acrobat Reader XI what excludes all users with Windows lower than Win 7.
I know that there must be a way to create PDF Forms which can handle saving also in lower Reader versions then XI, because I use a form of a insurance company which I is able to do so ... and that since Acrobat Reader 7.x!!!
Where ist the button, trick, or whatever enables this feature in older Reader versions?