I've created some documents with file attachments (i.e. images), in a field called "NewsTeaser".

I want to make these attachments available to download (i.e. available at a publicly accessible URL) within a transformation.

I've used:

GetDocumentUrl("NewsTeaser",Eval("NodeAlias"))

and

GetAttachmentUrl("NewsTeaser",Eval("NodeAlias"))

Neither function works. The URLs generated by both seem to require a login to the CMSDesk in order to view them.

Why don't these work? What should I use?

(I can't use GetImageUrl() because I need to add custom class names to the resulting image element).