I tried creating bookmarks from a button as follows (in JavaScript):
event.target.bookmarkRoot.createChild("my bookmark", "this.pageNum = 0;");
and it works even after I save, close and re-open the form in Acrobat Pro. Of course, if you open the form in Designer, save, close and then re-open in Acrobat, they won't be there anymore because annotations, such as bookmarks, get stripped-out when PDF documents are opened in Designer.
You might want to try dynamically creating the bookmarks every time the form is loaded.
I've attached two sample forms:
CreateBookmarksOnLoad.pdf which dynamically creates bookmarks when the form is loaded (note the guard form variable to prevent creating them every time a Layout event is fired) and
CreateBookmarks.pdf which creates bookmarks at the push of a button (you should be able to save, close and re-open this PDF
all within Acrobat and have the bookmarks still work.
Stefan
Adobe Systems