Перезалил аддон.
В конец inf файла добавлена секция [User.Tweaks.Add.Reg] в которую можно добавлять пользовательские твики.
Код:

HKCU,"Software\Microsoft\Internet Explorer\SearchScopes","DefaultScope",,"{B2A025AA-2242-4E2F-8FC6-6DC64A736A80}"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes","Version",0x10001,01,00,00,00
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{058C66B2-4CB7-4EFD-BC18-D2ACA9E04F73}","DisplayName",,"Wikipedia"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{058C66B2-4CB7-4EFD-BC18-D2ACA9E04F73}","URL",,"http://ru.wikipedia.org/wiki/{searchTerms}"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{0633EE93-D776-472f-A0FF-E1416B8B2E3A}",,,"Live Search"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{0633EE93-D776-472f-A0FF-E1416B8B2E3A}","DisplayName",,"@ieframe.dll,-12512"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{0633EE93-D776-472f-A0FF-E1416B8B2E3A}","URL",,"http://search.live.com/results.aspx?q={searchTerms}&src={referrer:source?}"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{399C4D3F-AB20-4D91-A26A-06F47F9EA438}","DisplayName",,"Rambler"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{399C4D3F-AB20-4D91-A26A-06F47F9EA438}","URL",,"http://www.rambler.ru/srch?set=www&words={searchTerms}&btnG=%CD%E0%E9%F2%E8%21"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{95F663C0-C370-4955-8B39-63069DB1F6C0}","DisplayName",,"Яndex"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{95F663C0-C370-4955-8B39-63069DB1F6C0}","URL",,"http://www.yandex.ru/yandsearch?stype=&nl=0&text={searchTerms}"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{B2A025AA-2242-4E2F-8FC6-6DC64A736A80}","DisplayName",,"Google"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{B2A025AA-2242-4E2F-8FC6-6DC64A736A80}","URL",,"http://www.google.ru/search?hl=ru&q={searchTerms}&btnG=%D0%9F%D0%BE%D0%B8%D1%81%D0%BA+%D0%B2+Google&lr="
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{FA6CC280-3AEA-4DC3-9C5B-9B729779EC31}","DisplayName",,"Microsoft"
HKCU,"Software\Microsoft\Internet Explorer\SearchScopes\{FA6CC280-3AEA-4DC3-9C5B-9B729779EC31}","URL",,"http://search.microsoft.com/results.aspx?mkt=ru-RU&setlang=ru-RU&q={searchTerms}"