How to choose in stdin stdout of Eclipse

In the NIos IDE, the options "null" "jtag" "lcd"can be selected in these area

stdin

stdout

stderr

in the "system library".

But in the Eclipse, where to choose the option "null"?

If I input the "null" to this label as below, it still output in the lcd!

stdin device name null

stdout device name null

stderr device name null

It means it dont work!Am I wrong?

How do I make this cpu dont output the data to the lcd terminal ?