This article addresses SSL verification for customer domains who's domains are added through a Cloudflare Hosting Partner. Essentially in order to issue SSL certificates, you simply need to proxy the record through Cloudflare and the SSL certificate will be automatically issued within few minutes.
Please be advised pausing or re-delegating away will prevent this from occurring so you need to ensure the record remains proxied during this time. Typically our new universal SSL certificates provision in a couple of minutes.
At the moment the only officially supported validation method for partial zones activated via a hosting provider is over HTTP. We will add DNS as an alternative method at a later date.
If you would like to complete validation using HTTP without proxying through us, this can be done by using the Cloudflare API, please reach out to partnersupport@cloudflare.com.