I used to do this all the time with DSMapbook and still do on my 9.3.1. It would be a very nice addition to DDP.
One workaround is to disable the DDP, export to pdf and then re-enable it. But that doesn't go well if one has page definitions, one of the great things about DDP. If one has Adobe Acrobat one can export to eps and then open it in Adobe to convert it to a pdf without rasterization, but that loses the pdf layers and georeferencing. There was some comment that hinted 10.1 would allow DDP to export to bookmarks but I haven't seen that and don't know what it might lose (e.g. page definitions).