Documentation on integrating with RoboHelp is sparse.  Here are some things I discovered by reading the JavaScript source (which looks like Win32 UI code out of the 1990s):

To link directly to a topic for context-sensitive help:

index.html#page.name.htm

To show the Index pane:

index.html#>>pdb=ndx

To show the Search pane:

index.html#>>pdb=nls

To show the Glossary pane:

index.html#>>pdb=gls

With these links, you can create a Help menu in your application with links to all of the appropriate pages:

If you have the patience, you can tweak the RoboHelp source to provide some pretty cool value-adds.  For example, I was able to add keyword search highlighting: