Stupid question about Hexen: the R key ..help

[Aulin]

Hello i'm using Doomsday 1.9.0 beta 6.5, i tried to read the faqs but i dint find out an answer

i just wanted to use the hexen "NRA" cheat command in game in order to get all weapons and unlimited mana, but when i press the R key a chat mode opens and it wont let me type the cheat.

I had the same issue on Heretic, but i simply changed the chat key assigment on "controls" menu (Red chat)

But when i go in control menu under hexen there is no way to change the R key assigment, simply there is no "Red chat" line.

Anyone can help me? how can i use the R key freely and remove any assigment to that key?

Thanks