Back in September 2014 I purchased the commercial version of the ISPConfig module for WHMCS from Germanius on the ISPConfig forum and for the most part the module worked, however there is an error that is being reported by many users in which you get the error "SOAP Error: no_server_error" when you enable the create website function. After having no joy trying to get this fixed by Germanius, I finally got frustrated enough that I ended up writing a new version of the module and released it as opensource under the GPL3.
You can find the module at http://www.github.com/cwispy/ispcfg3
For instructions on how to configure the module, see the wiki https://github.com/cwispy/ispcfg3/wiki
For support or other issues, please see the thread on HowtoForge