Hi,
If you want to stick with RoboHelp, you might use it to build
an HTML Help 1.x (.chm) file and then convert this to Help 2.0 with
FAR — a very quick process, and usually straightfoward.
Obviously, though, this may mean that you can't take advantage of
all the facilities of Help 2.0, such as dynamic help.
If RoboHelp doesn't provide the option to build Help 2.0
files then it's not so different from most other help authoring
tools. I'd imagine that most HAT vendors have taken a look at Help
2.0 at one time or another and, perhaps wrongly, decided that it's
too marginal a format to waste development hours on. To my
knowledge, only Doc-To-Help, Help & Manual, HelpStudio, and FAR
are capable of outputting Help 2.0 files.
Pete