Some programs (e.g. ms html help viewer) have zoom-in features that only seem to work when you mouse wheel scroll.
Is there a way to emulate mouse wheel scroll using the keyboard?
It's possible with AutoHotkey.
Try this script for instance: Using Keyboard Numpad as a Mouse. It uses the Numeric Pad to emulate a mouse. When on, NumPad+ and Numpad- emulates the mouse wheel.
(Assuming Windows): Check out AutoHotKey, it can remap the Mouse Wheel.
From the docs: