Password protected PDF Bookmarks not displaying in Preview

[perelus]

Greetings,

I have been struggling to understand why I cannot see the bookmarks in Preview when using a password protected pdf .

I have produced a manual in InDesign CS3 and exported it as pdf. Provided I do not set a user password I can see all the bookmarks in Preview with no problems. However, as soon as I add a password, the bookmarks disappear. The thumbnails are OK, and in the bookmark bar I get one entry, which is the file name.

If I open the protected pdf in Adobe reader all the bookmarks are displayed.

Is this a known problem with Preview?

(I had a good google around but could find very few clues)

Thanks