Havana has not yet wrapped, nor is our revised documentation available for the various changes / enhancements made in NetApp's Cinder drivers. Certainly, iSCSI is one of the two transport protocols supported by our Cinder drivers in Havana though. Could you be more specific about the problems encountered?
If you have security enabled you can change the netapp_server_port to 443 and the netapp_transport_type to https. Please note the IP address is the management IP not a data LIF.
Once these changes are in place you can restart the cinder daemons to test. You should be able do a "cinder create 2" and see a 2 GB lun created and mapped on the vserver within the openstack volume. The lun name will have the volume ID in it's name. You may need to create the openstack volume.
OpenStack / Cinder APIs are REST APIs. As long as the storage controller is set up properly, and our driver is used by Cinder all management can be done with the Cinder REST API. Setting up the storage controller does require some manual operaitons -- please refer to the documentation for how to configure the C-mode direct iSCSI driver.
Openstack / Cinder will create LUNs for you on the vserver. You need to create the vserver and flexvol manually beforehand. There is no way to import existing LUNs into Cinder currently. If you have a bootable image, it needs to be registered with the glance image service, then Cinder can copy that image into the LUN for you.