.htaccess doesn't work with IIS which is the webserver that .Net normally runs on (PHP normally runs on Apache which does use .htaccess). What version of IIS are you using? What are you trying to achieve with .htaccess?
Well create it then, it wont do anything though on IIS6. Depending on if you were wanting to do URL rewriting or access control using the .htaccess will dictate on how you achieve the same on IIS