Keymapping
Why don't my key.user3 and key.user4 work?
Key.user3 and key.user4 work by default for runtimes PFLT and PFLN. If you are using a DOS runtime such as PFL2 or PFL3 under Windows NT, than you need to add the following line to your CONFIG.NT file:
device=%SystemRoot%\system32\ansi.sys /x
(Please refer to the documentation for further information).
Termchar terminfo keymapping Wyse 50/60 terminals, Unix.
See terminfo.