The Microsoft Visual Studio help viewer is called DExplore.exe Lauch it with a /? command line parameter in order to show a usage summary:
This is the output I see from DExplore v8 (that shipped with Visual Studio 2005):
Available command line options:
/helpcol ms-help://<Namespace> Use specified help collection.
/filter <filter name> Use specified filter.
/LCID <locale id> Use specified language.
/LaunchNamedUrlTopic <named url> Display the topic for the specified named url.
/LaunchFKeywordTopic <keyword> Display the topic for the specified keyword.
/usehelpsettings <settings token> Use help settings from the specified application token.
We only use the /helpcol ms-help://yournamespace parameter in Document! X, and these parameters are not documented anywhere as far as I know. /helpcol would be sufficient just for opening the help for viewing.