Embedding HTML code into a WinForms application.

Hi, I've a somewhat unusual feature to implement and I don't know if it can be done without much effort.
A WinForms application has a help file (well, not HTML help, but simply a HTML file with a reference sheet). When user presses F1 button a form with a web-browser control in it displays showing this file. The client wants this HTML file to contain buttons/checkboxes which a program should respond to.
For example, if a user clicks a HTML button in the help file some value should appear in a textbox on the main form, etc. Is it altogether possible?

(the HTML file is local)

:confused:

Well, I've got it working, but I don't particularly like the solution I've found.
I've established a httplistener on 127.0.0.1:8001 and added a POST HTML form to http://127.0.0.1:8001 from my help file. This works but too many things may go wrong with this approach. Is there a better way of doing this?