tracking center

Hello guys, I want to store log mail in the tracking center over 3 months. How can I do that because normally mail in the tracking center will be deleted after 7 days? Please help me solve that.

in the tracking center i can filter by sender, receiver, time-span and "filter" (which appears to be some simple text-matcher, without a regex engine). i find that i would also like to filter the results based on the delivery state, e.g. limit the display to entries that are accepted/delivered...