Tried http post doesn't work

I wanted to try the example here

http://www.codeconscious.com/rebol/rebol-net.html#HTTP

print read/custom http://babelfish.altavista.com/translate.dyn reduce ['POST {text=REBOL+Rules&lp=en_fr}]

Since the page has changed since I modified it to

write clipboard:// read/custom http://babelfish.altavista.com/translate.dyn reduce ['POST {trtext=hello+world&lp=en_fr&btnTrTxt=Translat开发者_高级运维e}]

It does return an html page but it doesn't contain any translation. What did I miss thanks ?

There are a lot of hidden variables which you haven't included ...

 <input type=hidden name="ei" value="UTF-8"> 
 <input type=hidden name=doit value="done"> 
 <input type=hidden name=fr value="bf-home"> 
 <input type=hidden name=intl value="1"> 
     <input type=hidden name=tt value="urltext" > 

POST with Rebol works, so my guess is that the babelfish page has become more complicated in the time since the writing of the tutorial.