Sitemap url scheme in robots.txt

Hi,

I use https on project. In my robots.txt file I cant get sitemap url to have https scheme.

In site admin I have domain name without scheme, and name with https scheme. Even if both have no scheme, I have sitemap url with http.
ROBOTS_USE_SCHEME_IN_HOST = True
How can I setup sitemap to hame https?

(but sitemap looks proper with protocol = 'https')
