Adobe Sign: autodetection recognizes Checkboxes as Radio Buttons

When I create a word document with several checkboxes in a vertical line underneath each other, Adobe Sign turns them into Radio Buttons instead of checkboxes when I use the automatic field detection function.
If the checkboxes are placed randomly somewhere in the word document, then Adobe Sign DOES autodetect them as checkboxes.
I want it to do this always! Can this be fixed? 

(BTW Using tags in the word template is not the solution work for me, because I use a nice background  for my templates and the tags don't come out transparent in Adobe Sign but come with a white backgroundm which makes it look ugly)

Who can help?