Weird problem with acts_as_attachment

I'm using acts_as_attachment to build a simple portfolio. Items has and belongs to many attachments, but when using this:

<% for attachment in @item.attachments %>   <%= attachment.id %><br/>   <%= attachment.filename %><br/>   <%= image_tag attachment.public_filename, :size => attachment.image_size %> <% end %>

in a view I get:

1<br/> oxmo.png<br/> <img alt="Oxmo" height="536" src="/attachments/1/oxmo.png?" width="800" />

the filename is fine but the id for that image is 14, so the public_filename is all wrong! The id for the item is 1 but shouldn't attachment.id in this case return the id of the attachment??

Thanks in advance!

Mikkel Bech