Hello giorgino,
i haven't added anything in connection to the attachment-system in this addon, so i didnt belive, that this problem has to do anything with it.
as far as i can see, you are using nginx and vbseo rewrite for attachments? an am i correct, that you problem is, that attachment-urls like
http://www.propit.it/attachments/f66...-.4.09-005.jpg resolve into an 404 error? since our forum use nginx and vbseo too, i think i can help you anyway.
vbseo will rewirte the url of yout attachments to something like "attachments/f66/372d1280162113-firma-nostro-libro-ospiti-stlegdv14-1-1-.4.09-005.jpg". in our nginx configuration, nginx deliver jpeg directly and doesnt check each time if they exists, so it could use vbseo if it didnt exists.
since we didnt wanted to change this behavior of nginx we drop the rewrite of attachments with vbseo. hope this could help you.
Best regards
Sebastian