Can you fix this? Do you want .html extensions?

I have a solution that works minus this one problem with .html urls.  Fantastic...

But in the admin, for the wysiwyg designer there is an error only for that section, like on the product update description field.  I tried to add .html extension in the <compilation><buildProviders>, but cannot get it to work.  Everything else is a dream!  Will pay for answer.


Server Error in '/' Application.
There is no build provider registered for the extension '.html'. You can register one in the <compilation><buildProviders> section in machine.config or web.config. Make sure is has a BuildProviderAppliesToAttribute attribute which includes the value 'Web' or 'All'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: There is no build provider registered for the extension '.html'. You can register one in the <compilation><buildProviders> section in machine.config or web.config. Make sure is has a BuildProviderAppliesToAttribute attribute which includes the value 'Web' or 'All'.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.