Huh? I've seen her mention something like "I did all music for the first Castlevania, including all its data", on a lot of places. Maybe she was actually referring to the MSX version in that post Prime Blue is linking to?
Edit:
She also says in this video description: "
I didn't program the music or do the sound effects for Castlevania. I only made the music and the data for it.".
And under the "About Castlevania etc." it says:
Raven : In the first game, you are credited not with your real name, but with the name James Banana. Was this your pen name? Was it the name that your team gave you?
Kinuyo : I left the company Konami and so it was their way of adding me to the credits. My real name, Kinuyo Yamashita, appears in other games.
Oh, and in this description, it at least says she did Vampire Killer and Wicked Child:
http://www.youtube.com/watch?v=XptUDCl_RXk