You can provide an HTML page as part of your package or a web address (URL) that Net View will load when the user presses
the help button: 
To specify a help location for an on-the-fly Custom Property object:
Use the PPGLayout.SetAttribute or PPGLayout::PutAttribute method with the siUIHelpFile enum. For example:
oLayout.SetAttribute( siUIHelpFile, "http://www.softimage.com/support/" );
To specify a help location for a plug-in based (self-installing) Custom Property object
Use the SIObject.Help or PluginItem::PutHelp or PluginRegistrar::PutHelp property in the XSILoadPlugin callback:
in_reg.Help = "http://www.softimage.com/support/";
Name your HTML file with the name of your plug-in and add it to the doc subfolder. Softimage will find your HTML page automatically. For example, this is a sample file structure for a typical self-installing plug-in containing a Custom Property:
C:\Public\Plugins\MyFabulousProperty.dll C:\Public\Plugins\doc\MyFabulousProperty.html
If the self-installing property is in an Add-on directory, use the add-on help mechanism. See Add Help for the Add-on.