Ok. Thanks.

With coin control enabled I was able to see the change addresses (and their balance, even if sync is not finished; but I do not see the confirmations yet of cours).

Regarding backups:
I have some backups on external usb drives of my wallet. So I have to replace those over and over again?

Ok, thanks for the information.
So for the change a new address I being created and automatically added to my wallet?

In Bitcoin QT when I show all my "receiving addresses", I can only see my one address. Not the other one where the 0.9BTC went to. I guess this is because Bitcoin QT is not fully synchronized yet?

I just sent a 0.1BTC transaction. Now it shows that I also paid 0.9BTC to another address (http://imgur.com/pUdOTPG). I used the Bitcoin QT client to do the transaction. There it told me that I spent 0.00001130BTC transaction fee. The Bitcoin QT Client is not fully synchronized yet (about 1 year behind). Could that be a problem?

Hello,

I would like to trade some bitcoins between btcchina and the european exchanges (arbitrage) as the price difference is really high.
This gives the opportunity to earn a bit of money and would help the bitcoin community in general, as it levels out the bitcoin prices all over the world and thereby helps to make bitcoin more stable.

I am looking for someone in China who would be interested in doing so. I would buy bitcoins cheap in Europe, send them to you in China, you sell them more expensive and send back the money to Europe. We would share the profits 50/50.

Of course the biggest question is trust and a lot of people will scream scam. But I think there are ways how to establish enough trust between two persons to do some reasonable trading. If you are interested send me a message and we can talk more about this plan and how to make it trustworthy.

To the community:
Please forgive me that my first posts are not in the newbies section. But I am mining bitcoins since 2011 and following all of this for over 2years. I never needed to create an account at bitcointalk in the past, as I always found answers by using the search.