You might have found it by now, but, the option is very much there.

See that you're not attaching more that 50 attachments. That's a limit per post. If you attach more, t might show up in the editing panel but would never show up in the published topic. Hope that helps. :)

1 suggestion. We get an option to post a new topic in a Forum, Topic or User when we first create a topic. So, instead of that being visible only when first creating the topic, it could be better if it's visible every time the topic is updated. That way, we can add where to post the same topic and where to delete from. It will probably also copy the attachments. Also, the security: topic can be edited only by its creator, I suppose (I don't have any member in my private team other than me, I have created a few private teams just to backup my files there and sort them as topics). So, if it's editable only by the creator, then, only he/she can copy/move the topic. So, can this be made possible?