"scriptPubKey":"WHERE-DO-I-GET-THIS-FROM?"
Run "validateaddress" on the address. It shows the scriptPubKey as one of the outputs.
I'm sorry, but I can't get it to work. When I run validateaddress with the sender address and use the pubkey it returns, signrawtransaction only returns the hex again and says it failed.
Is there any step-by-step example that guides through the entire process?
Also, does it matter if the client is not synced?
It doesn't matter if the client is synced. You should unlock the wallet with the walletpassphrase RPC before trying to sign a transaction. Other than that, maybe you could show more details. What are you typing, and what does the error say? "I failed" isn't helpful.