When opening the Run Once dialog and the "Initial Run" can be enabled (sysprep for Windows and cloud-init for Linux) the "Initial Run" subsection is hidden until you open the "Boot Options" subsection and select the "Attach CD" checkbox. (its not re-hidden after you un-select the checkbox).
merged at: http://gerrit.ovirt.org/gitweb?p=ovirt-engine.git;a=commit;h=8bac2fb67e0ee6208b339f26035524fc51f81507
oVirt 3.3.1 has been released