Alan,
Did you mean ALT or ESC?
In either case, WordPerfect 4.2 for the Rainbow came in two different
keyboard templates: the 4.1 version and the VAX version. On the VAX
version, ESC is not where DEC put it, but on F7. On this version, I don't
believe Shift-Ctrl works for ALT (I don't think anything does). On the 4.1
version, I believe ESC is where DEC put it and Shift-Ctrl works for ALT.
If you have Smartkey 5.0D, you have a built in ALT equivalent.