This is from the XA30.5 Owners Manual;
"... The output binding posts will accept either bare wire or spades. (Regulatory agencies in many countries have banned binding posts that will accept a banana plug, forcing us to abandon this option.) ..."
However, the XA30.5's speaker binding posts look like they are the same as the posts for the 12V trigger on the XA60.5 and the XA100.5. If that is the case, then the cap covering the end of the post is secured by a little gold pin that is driven into the opposite end of the cap (closest to the amp). To see it, back out the post nut all the way on the post screw. Just drive out the pin with a small punch (or small drill bit) and the cap will come off the end of the post. I did this on both my XA60.5s and my XA100.5s.