How to use sendTransaction instead of Mist for sending pre-sale ETH ?

UB42

I've got pre-sale ETH on my Mist "account"
(Ethereum-Wallet-linux64-0-8-1).
I would like to send it,
but normal Mist sending doesn't work.
1) Is it a good idea to use eth.sendTransaction() instead ?
Or is Mist using eth.sendTransaction() as well and
because of Mist is not working
eth.sendTransaction() would neither ?
2) I don't know the exact syntax for eth.sendTransaction().
I can go to ./resources/node/geth/ directory and
type per command line something like:
./geth --exec "eth.sendTransaction({from:'0xADDRESS',to:'0xRECIPIENT',value:10,gas:21000,gasPrice:50000000000})" --unlock '0xADDRESS' console
Is this command line correct ?
I would like to send 10 ETH.
is "value:10" the right unit ?
Thanks.