Please find below the SSLReseller WHMCSmodule. You will also find some useful guides to setup and configuration.

All in all, 10 mins and your first Certificate product is there in whmcs :-)

Main CNOC info : https://support.netearthgroup.com/index.php?/netearthone/Knowledgebase/List/Index/7/cnoc-api

Setup Live and Test accounts :
https://support.netearthgroup.com/index.php?/netearthone/Knowledgebase/Article/View/18/7/creating-demo-test--live-accounts-and-setup-the-api-keys

Quick Setup of WHMCS (uploading/installing module) :
https://support.netearthgroup.com/index.php?/netearthone/Knowledgebase/Article/View/21/7/whmcs--installing-the-module

Quick Setup of Products in WHMCS (configure products upto 3 years) :
https://support.netearthgroup.com/index.php?/netearthone/Knowledgebase/Article/View/20/7/whmcs--quick-setup-of-the-module-for-all-cert-types-1-to-3-years-ev-max-2

Offering the free Trial DV Cert :
https://support.netearthgroup.com/index.php?/netearthone/Knowledgebase/Article/View/24/7/offering-the-free-globalsign-domain-validated-certificate

If you require 4.5.* WHMCS templates, please download them here :

https://support.netearthgroup.com/index.php?/sslreseller/Knowledgebase/Article/View/29/2/whmcs-45--templates-with-the-sslr-code-added