I have recently purchased a Samsung PS42C91HD and have managed to get all the Activites (Watch DVD / Play Game) working except moving from another activity to Watch TV. The issue is that the original Samsung remote has a Source button that cycles through AV1 (Wii Input) and SVideo (DVD Input) but to watch TV you need to press the TV/HTV button on the remote. I cannot figure out how to tell the Harmony 880 to do this? Suggestions?

The brute force method is to add the TV/HTV command to the beginning of the watch TV activity, but that might mess up the other inputs later. If you call support they should be able to fix it for you.

I checked the Samsung PS-42C91HD command list and it has many discrete input commands. Try them in device mode making sure they are discrete and not toggle/cycling. If they work properly, then reconfigure the Device Adjust Inputs to use the discrete method (Method 2). Note: Many devices supports discrete commands although these commands may not be on the original remote.

I have the Samsung PS50C91HD and the 785 remote.
Could not get it to work - exactly the same problem as you.
After 2 days of frustration, called the support line - Spent 3 hrs on the phone trying various things - no luck.
Call has apparently been escalated - and they will get in toich with me within 5 working days.
Today is 5th working day and no contact yet.
I called back about 1 hr ago and was told they need more time - about 3 more days!!!!

Quite frankly, their support sucks.

Logged it via support 2 weeks ago, called yesterday and was advised the same - excalated and need more time.

Will try the discrete mode tonight and let you know the response.

I tried the discrete codes and managed to get it all to work, thanks. For those who need it:

I added a new button called HDTV and used my TV remote to learn the HTV function
In Device Adjust Inputs used Method 2, with the available inputs of TV, AV and SVideo
Created inputs of TV to select the newly created HDTV button, AV to select TvVideo and SVideo to select SVideo.

All works fine now.

Thanks all for your help, and it was faster than Harmony customer service.

Update from post Aug 24.

Still waiting for Harmony's fantastic Support Dept in Canada to actually make the phone they promise to make every day.

This is a crap product with more crap support.
Disgusting and pissed off doesn't even start to describe my feeling to this company.

Harmony support finally got back to me with an email advising that they updated my remote's profile and to upload the new settings. Plugged in the remote, pressed update and what do you know - the settings they added in were all wrong and I have to go back and put my fix back in place. It would be good if support knew what they were doing.
Alas, my problem is resolved for now, until support go and do something else wrong.