I almost did what you did a couple of times but fortunately there is a warning asking you if you want to really do this... I assume that if you post you haven't backed up your mail file.
Not sure how to retrieve but to preserve you need to keep the account and make it inactive.
Bop 'til you drop
MB Air 15 | i7 | 8 Gigs of shiny DDR RAM | 512 blistering SSD
iMac 27 i5 16Gig 1TB
Time Capsule 1TB
iPhone 5: "It's fast..." & Sony noise cancelling headphones
Canon 7D proper camera with nice L glass and Lightroom 4