EyeonTips:Script/Reference/Applications/Fusion/Classes/Object/SetData
From VFXPedia
You can use SetData to add a key called HelpPage to any tool. Its value can be a URL to a web page (for example a link to a page on Vfxpedia) and will override this tool's default help when the user presses F1 (requires Fusion 6.31 or later). It's most useful for macros.
Background1:SetData("HelpPage", "http://www.vfxpedia.com")