There are three main issues.
You must use an emulated VT100+ keyboard
You need to set that up explicitly in Putty (TERMINAL > KEYBOARD). In Linux, you set this up via the environment variable TERM. The default TERM of xterm is good. Some people like the setting on ansi. You can set it explicitly to vt320 if you like. In all cases, you must make sure that your terminal emulator isn't trying to be helpful by stealing the F1 from you to display help.
Screenman drawing on Putty
For some reason (somebody help please to find out; I can't do everything) Putty does not display the Screenman lines as lines but rather as qqqq. To fix that, go to WINDOW > TRANSLATION and change the remote character set to ISO-8859-1.
Page Up and Page Down
This has to do with why Fileman Word Processing fields didn't recognize Page Up/Page Down & Home/End.
Reading the code in DDGLIB0, Page Up and Page Down will be defined ONLY IF your VISTA terminal type is VT-220 or VT-320. Don't set terminal to VT-100 or -102.
Home and End are a very interesting problem.
Putty and Windows Telnet reads Home, End as *27,"[1~",*27,"[4~" Linux console reads Home, End as *27,"[H",*27,"[F".
Every reference for VT320/220 I found on the Internet says that the Linux mapping is correct (!!) and the Putty and Windows stuff not correct.
I found this reference from a guy who writes Video Games very helpful in understanding this: 
So, believe it or not, VISTA VT220/VT320 is adapted to Windows and is not standard according to the VT manuals. Pretty unbelievable; but I took the time to prove it.
So, here is the final piece of advice:
1. If you are on Linux and using only Linux without Putty, you need to change the fields FIND and SELECT to be (once for VT220 and once for VT320):
Select TERMINAL TYPE NAME: C-VT220 Digital Equipment Corporation VT-220 terminal FIND: $C(27)_"[1~"// $C(27)_"[H" SELECT: $C(27)_"[4~"// $C(27)_"[F"
2. Just use putty everywhere. It emulates Windows Telnet closely.