I have several pdfs stored locally. I have file:/// links to these pdfs in my local TiddlyWiki. When I open one of these, Firefox opens it inline, as expected. Now I want to add annotations to these pdfs as I read them. Since I have not found a way to do this when viewing them inline, I used the open in Preview feature in the context menu. This works fine, but when I want to save, Preview complains that the document is locked. It appears Firefox creates a temporary copy that it gives to preview to open, instead of the real thing. Is there any way to work around this? I want to either be able to save the annotated files from preview or to do the annotations directly in Firefox.

I am using Snow-Leopard with Firefox 3.6.

Edit I can annotate the pdf just fine when I open them in preview directly.