Hello,
I just want to inform you guys that I already built a Drupal module Solving the registration issue in OwnCloud all what you need to have a Drupal Installed and WhyWebs Multistep registration module then register on Drupal after you fix all the needed fields in Multistep module configuration to connect with your OwnCloud Database.
As soon as any user register in your Drupal site it will automatically register your user into OwnCloud
https://www.drupal.org/project/multistep_registration
please comments