Communication Channel IDOC tipy and SENDER

Hi experts!

We have an XI SP14.

I have read that it is not needed a communication channel to send Idocs from R/3 to XI but, if we try to set this communication channel, we are not able to select the "Sender" option in the comm. channel. We have never used this kind of comm. channel to send Idocs from R/3 to XI so, I wonder why we are having this problem.

Do you know if this is a problem with the XI version or is it customizable?

If it is customizable, do you know where is this set up?

Thanks in advance!