Yes, ACMESharp has supported DNS-01 and HTTP-01 from the start. @zlamma, I queried your DNS record that you quoted above and it appears to be resolving correctly.
If you’re using the “manual” challenge handler then it does not matter what your local web server or operating system are, as long as the DNS service is Internet-routable and publicly reachable, which it appears to be fine I was able to query it.
Are you running this against the PRODUCTION ACME servers, or STAGING?