The way mines is set up, my mail is actually exchange mail so I have a OST file at the top of outlook. I then have my old PST file that I worrk from just beneath it. They set rules on my exchange mail so that anything that comes through it, a copy of it is moved to my PST inbox. Same with sent. My contacts and calander are in the OST file. There are then rules to auto achive (delete) my OST inbox and sent file to delete anything older than 7 days.
With this setup, as long as a copy stays in my OST inbox then there is a copy on the exchange server so I can view the attachments. I also created a sub folder to my OST inbox where I store an address list and a spreadsheet with useful info. I can view that folder from my BB also. I can give more details if you like