There is one particular whitelist in AutoCAD concerning online help. Only the domains on the list will be accepted by help browser, and the others will be forwarded to system default browser.
This white list is hardcoded in 2013, but in the 2014, developers can now create below registry key to add their own domain into it. The default value of this key is “autodesk.com”.
HKLM\SOFTWARE\Autodesk\AutoCAD\RXX.X\ACAD-XXX:XXX\SupportedUrls = "autodesk.com, mycustomdomain.com"
Here is the VB.Net code:
Public Shared Sub InvokeHelpWeb2()
Dim doc As Document =
'Press F1 while prompted to input value