rspec users - Jan 2008 - attachment_fu with fixtures

Dear list,

I can''t figure out how to use fixtures with attachment_fu. I know how  
to use files with RSpec in my controllers,   
BackgroundPhoto.create(:uploaded_data => fixture_file_upload("files/ 
some.zip", "application/x-zip")), but this does not work with  
fixtures(obviously). More importantly I have no idea where to start...
Can someone shed some light on this?

With kind regards,
Harm