I can confirm that this method does not work for steam games. The problem is that one steam game may have a "C:\Program Files (x86)\Steam\Steam.exe" -applaunch 240" shortcut, while another may have a "C:\Program Files (x86)\Steam\Steam.exe" -applaunch 21660" shortcut. They both link to the same icon and exe, yet it shows up as a different icon on the desktop for some reason. Then to top it off, the default AppExePath shows "C:\Users\Hugh\AppData\Local\Microsoft\Windows\GameExplorer\{B9D8EA68-7DDE-405E-BED3-7763D71B1CFE}\PlayTasks\0\Play.lnk", and when you change it, the link no longer works in the Games Explorer.
I've tried every way I can think of to get it to work, but it just doesn't. My games are Counter-Strike Source and Street Fighter 4 which are run through "Steam.exe".