Unfortunately, none of these works. How's that possible? What I'm doing wrong?
Are you testing any of these on the Mainnet?
No because I do not have enough bitcoins. However, I've seen many sending with "pseudo-fixed" fees on testnet too.
It's my understanding that testnet does not require any fees. This may be lending to your problem.
Also surely you have enough Bitcoin to test some 0.0001 sending fees. Just send them somewhere and bring them back (such as to Coinbase, etc).
Testnet requires fees too!
Then how do miners mine those bitcoins?
Whatever, I've finally found the parameter: minrelaytxfee =
TX example: http://tbtc.blockr.io/tx/info/90e8519b747117df73cd244d40b26c7ab3e962fbd7b3106bfa9995da85c072e2