How do I add new applications to the "Set Default Programs" list in Windows Vista/7?

I've successfully added Chromium to that list, here is how I did it:

If you want to do it to your program, just replace all that seems necessary from following regfile.

For Chromium, replace at least the path: C:\\Program Copies\\Chromium\\chrome.exe with your chromium path, it is in two places at the following reg file.

Put following snippet to somefile.reg:

Windows Registry Editor Version 5.00

; Infamous capabilities:

[HKEY_LOCAL_MACHINE\SOFTWARE\Chromium\Capabilities]
"ApplicationDescription"="Chromium - Beta Google Chrome"
"ApplicationIcon"="C:\\Program Copies\\Chromium\\chrome.exe,0"
"ApplicationName"="Chromium"

[HKEY_LOCAL_MACHINE\SOFTWARE\Chromium\Capabilities\FileAssociations]
".htm"="ChromiumURL"
".html"="ChromiumURL"
".shtml"="ChromiumURL"
".xht"="ChromiumURL"
".xhtml"="ChromiumURL"

[HKEY_LOCAL_MACHINE\SOFTWARE\Chromium\Capabilities\URLAssociations]
"ftp"="ChromiumURL"
"http"="ChromiumURL"
"https"="ChromiumURL"

; Register to Default Programs

[HKEY_LOCAL_MACHINE\SOFTWARE\RegisteredApplications]
"Chromium"="Software\\Chromium\\Capabilities"

; ChromiumURL HANDLER:

[HKEY_LOCAL_MACHINE\Software\Classes\ChromiumURL]
@="Chromium Document"
"FriendlyTypeName"="Chromium Document"

[HKEY_LOCAL_MACHINE\Software\Classes\ChromiumURL\shell]

[HKEY_LOCAL_MACHINE\Software\Classes\ChromiumURL\shell\open]

[HKEY_LOCAL_MACHINE\Software\Classes\ChromiumURL\shell\open\command]
@="\"C:\\Program Copies\\Chromium\\chrome.exe\" -- \"%1\""

Then as usual with reg files, you must double click to run them.

To allow Chrome to appear in the Default Programs, use regedit to check the correct file path for chrome.exe appears here...

HKEY_CLASSES_ROOT\ChromeHTML\shell\open\command

if not, change the original executable file from whatever it was,

eg. > "GoogleChromePortable\App\Chrome-bin\chrome.exe"

to:

"C:\Program Files\Google\Chrome\chrome.exe" (or wherever your chrome is located).