PDF version 1.5 doesn’t work for metadata (apparently because it compresses objects to reduce the output size); save as 1.3 for it to be parsed correctly, and you’ll still need to set the filename to the title you want displayed in the main book listing, even though the device actually parses it out of the file to display on the detail page. Blech.
You can insert the metadata with pdftk as per bloovis, or some other tools (the full version of Adobe Acrobat works great, but is not exactly free…). LaTeX users can use a sledgehammer to swat this fly with the hyperref package, but you’ll need to use dvipdfmx -V3 to downrev the PDF output to 1.3.
Sony got their PDF software from Adobe (for the DRM, mostly), so their Readers don’t have this problem. Sadly, this means that a file generated for the Kindle will display much slower on the Sony, since the object-compression is quite useful.