you can change the retention period for mail on your Blackberry.
Click on the mail icon to open your mail view.
Click on the Blackberry button, to the left of your trackerball,
Scroll down to and click on Options,
Go to General Options,
Scroll down to ‘Keep Messages’,
You can choose the duration that suits you best, from 15 days, 30 days, 2 months, 3 months… 6 months or Forever !
Save the change, then escape from the menus.
Caveat: This is won’t retrieve old mails already discarded from your Curve, but new mail items will be retained until either the device storage is filled or the limit you chose is reached.
I suggest that older mail already discarded from your older mail wll only be available in your email repository.
Hope this helps.