In this link, http://download.pa.parallels.com/pbas/doc/PBAS_SDK/
There is a section "XML API", which connects PBA
(Parallels Business Automation) with external billing solutions.
Now, I want to ask, if any billing system supports this? For example, WHMCS, Blesta, etc? If there is a module (either free or paid), that would be great.
I need this because I need to complete a client's work.
Any help will be appreciated.