Well, IIRC Vocaloid is a Yamaha product, so it doesn't come as a shock that they would make an editor for Cubase. I toyed with that technology 4-5 years ago and it was a complete mess. The product was called "Diva." It was based on Vocaloid and it supposedly allowed you to have a soprano sing anything you wanted. It was very buggy and the editing process was long and complicated. Not to mention that the editor was so bad, it looked like it was developed for Windows 3.1... Hiring a singer was WAY WAY easier and cheaper (considering that time is money...)
I hope things are better now. But I'm not going to bother trying again any soon.
Desktop: i7 3770k, 32 GB RAM, nVidia GTX770 + GT640-DCSL fanless, 3 monitors (30" 2560x1600 + 2x 27" 1920x1080), 256 GB SSD (OS), 2 TB SATA III (audio), 3 TB SATA III (sample libraries), 3x 3 TB USB 3.0 (backup/archives), RME UFX, Win 8.1 Pro x64, Cubase 7.5, Sonar X3, Vienna Ensemble Pro 5.
Slaves: 2x i7 2700k, 16 GB RAM, 256 GB SSD, 3 TB SATA III, Win 8.1 Pro x64, Vienna Ensemble Pro 5.
Laptop: 17" HP EliteBook 8770w (i7 3820QM 2.7 Ghz/3.7 Ghz max OC, 16 GB RAM, 256 GB SSD, 1 TB SATA III), RME Babyface, Win 7 Pro x64, Vienna Ensemble Pro 5, Cubase 7.5, Sonar X3.