I attempt to create a token with the "automatic and selling" function as describe [here](https://ethereum.org/token#the-code). After having copy/paste the code (footpage)and deployed the contract no error message appears. But when I execute the functions "sell" or "buy" nothing happens. When trying to execute the function "buy" no field appears, which seems very odd to me because one should enter the amount they want buy/sell ...
Have any idea how to fix this ?

My expectations are that the sender account receive an amount of the new token equal to the amount of ether sent \* conversion rate specified, is this the purpose of this code ?

Thanks in advance !