Now I can read some private keys. None of them did the job....

The problem is, I think, the 1 bitcoin was never in my actual wallet (If so I should have spend! :-)).
The 1 btc was in the imported address section back in 2013 on this address 1MAUuNVNQgc4s5Cp15Xz9R7wD5DamwG5mL
I can see it is still there and it seems nobody can touch it!

I imported a json file in Multibit 0.5.17 and could export private keys. The balance is 0.

Blockchain.info support gives me this:
====
Wallet.aes.json backups can be imported here:

https://blockchain.info/wallet/import-wallet
====

It works (I have the password and .json file) but still balance is 0 and if I import the 1MAUuNVNQgc4s5Cp15Xz9R7wD5DamwG5mL
it stays a watch-only address and I don't have the key...

So dear bitcoin talkers, is my 1 bitcoin definitely lost or can anybody get it back? Reward = $ 1000

Eric.