[Adv. Guestbook] Animated smilies frees after inserting them

I am using Advanced Guestbook 2.3.1 and adjusted it to my style of webpage. Also I changed the smilies and they all work correctly. Just there is one thing: I am also using animated smilies, like here in this forum, and after I inserted one of them they stop moving. Now I see this is also the case when entering this message. I can still put these smilies in my message, but it doesn't look nice of course.

So my question is, how can I let them animate all the time when entering them in a message?

p.s. If you don't know what I mean, try to reply and put one animated smilie in the message, after you did that, they all are "frozen".