I had a request for this information, so figured I'd just come back here and post it.
Pic 1 - First off, the factory remote is nothing more than a simple four button panel with a PS2 type connector at the end. Buttons+wire+PS2 connector.... that is it.
So in order to make your own ......... just grab ya four micro buttons (I robbed mine from an old VCR button panel), a five wire bit of cable, and a male PS2 connector.
Pic 2 - The color coding I'll mention is the colors of the corresponding wires INSIDE the monitor itself.
Pic 3 - The color coded pinout of the PS2 port on the monitor.
"Shield" is the metal surrounding the pins. (can call it ground or common if you prefer)
Pic 4 - My craptacular example that I never felt the need to finish and make pretty.
Pic 5 - The PS2 end of my example. Part 1
Pic 6 - The PS2 end of my example complete. (with shield in place and soldered)
The button combination's are as follows.....
Shield + Yellow = Brings up OSD
Shield + Blue = Menu Navigate Clockwise
Shield + Green = Menu Navigate Counter Clockwise
Shield + Orange = Select / De-Select
Once a selection is made
Shield + Blue = Value UP
Shield + Green = Value DOWN
So as basic as button wiring goes.... there are four buttons total.....Shield is common to all buttons (common ground)...... and each of the four pins will be a function.
If there's any questions or further detail needed..... just let me know.