Hi, Gleedo,
You'll find some information on Office 2007 help here:
http://helpware.net/mshelp2/CollectionWizard/Office12Help.htm
In theory, it would be possible to extract the cascading
style sheets from an Office 2007 help file and use them as the
basis for a RoboHelp-authored project. Tools like
FAR let you extract
individual files from Microsoft Help 2.0 files (which is the format
employed by offline Office 2007 help).
Integrating your content into the Office 2007 help is also
possible but requires you to deliver it as a Help 2.0 file, which I
don't believe is possible with RoboHelp. On the other hand, you can
make a CHM file with RoboHelp and then convert it to Help 2.0
format using FAR. But the fact that your content will only be seen
if the user chooses to view help in offline mode — which is
not the default mode — probably makes this all a bit
redundant.
Pete