I have written entirely new code from scratch to read the wallet.aes.json files from BCI. Unlike the old code that was in MultiBit and has now been removed (because it was broken) this one will handle compressed keys correctly! It is contained in my wallet-key-tool.
https://github.com/prof7bit/wallet-key-toolto import *.aes.json into MultiBit:in wallet-key-tool:
* click "load..."
* in the file dialog select "Blockchain.info" from the filter drop down list
* find your wallet.aes.json file and click "open"
* enter primary (and possibly secondary) password to decrypt
* (optional) check balances by fetching them from BCI and make sure you have the right keys
* (optional, recommended) check and update the creation dates
* (optional) add/remove keys or import even more wallet files
* click "save as..."
* in the file dialog select "Multibit wallet (*.wallet)" or "Multibit backup (*.key)"
* choose a folder and file name to save the file, click "save"
* choose a password to encrypt
in Multibit
* open the wallet if you saved as .wallet
* or import into existing wallet if you saved as .key
Multibit will replay the block chain when first opened in MultiBit. To prevent syncing all the way back from 2009 you should make sure you updated the creation dates of all keys in wallet-key-tool before exporting to Multibit.
Make a backup of your MultiBit wallets
before you begin. Although my tool will refuse to overwrite existing files (it will only generate new files) you could import the generated .key files into your existing Multibit and once they are imported they cannot easily be removed again (of course you could then import the .wallet in my tool, remove keys and save it as a new .wallet and it will work without problems but nevertheless I recommend making a backup of all your original files before you begin experimenting with this)
Screen shots:
http://imgur.com/a/oUTtoDisclaimer: This software is not part of Multibit, its a separate tool, we are not affiliated, its using the official Bitcoinj and Multibit code to read/write the wallet formats but its a different tool and any bad things that might happen are solely your own fault (because you did not follow the above warning about backups of your original files)