In the MPE/iX environment, or in your login UDC, set the environment variable A_TERM to one of the following values, as appropriate.
hpminisoft hpreflection hpscreenjet
For example:
:SETVAR A_TERM "hpreflection"
If using an emulator that is not listed above, but the emulator is very similar to one of the above, set the A_TERM variable to the similar emulator, remap the special keys as described in Re-mapping Special Keys, and run a program in the debugger to test for correct behavior.