In https://github.com/bokkypoobah/TokenTrader/blob/master/contracts/TokenSellerFactory.sol, the function, I view the code of function TokenSeller::makerTransferAsset, because it calls "return ERC20Partial(asset).transfer(toTokenSeller, tokens);", because msg.sender is the man who create the contract and call the function, this should mean he fill the asset to the contract, and then he could withdraw it back from the contract.
In https://github.com/bokkypoobah/TokenTrader/blob/master/contracts/TokenSellerFactory.sol, the function, I view the code of function TokenSeller::makerTransferAsset, because it calls "return ERC20Partial(asset).transfer(toTokenSeller, tokens);", because msg.sender is the man who create the contract and call the function, this should mean he fill the asset to the contract, and then he could withdraw it back from the contract.