This is what the Harmony's Smart State technology is all about - remembering what state your devices are in.
From your Harmony member page, do the following:
- In the device list, select the "More Options" link for your monitor.
- Select "Adjust Inputs"
- Select "I flip through the inputs until I get to the right one (usually for TV, VCR, etc.)"
- Enter all of the inputs that your display has (in the order that they are cycled through when you press the input button)
- If your monitor skips unused inputs, select Yes to this option
- When prompted to select the cycling command, choose "Use these infrared commands" and then select the command that toggles the inputs (probably "InputNext")
- When asked what input your monitor goes to on power up, answer that it "Stays on whatever it was on when it was turned off"
- When asked if you can get to a particular input with your remote, answer no
That should do it. Afterwards, you can experiment with the commands available in device mode to see if there are discrete codes for selecting particular inputs on your monitor.