How to make attachments require approval?

[spamgirl]

I looked in Attachments in AdminCP, I looked in Message Attachment Options, I looked in User Groups, and I can't see where I can force attachments not to show until approved. What am I missing?

Thank you

--------------- Added [DATE]1315923901[/DATE] at [TIME]1315923901[/TIME] ---------------

Also, is there a way I can blacklist certain extensions for attachments? I was thinking I could set them as 0 in Attachment Options (I think that's the name of the area, I'm working from memory here) but I was hoping there was a better way.