vocaloid fans will be vocaloid fans. let her be, you'd never win. (talking from experience)
Well, not all vocaloid fans are weabos. Most of 'em are, though.
Anyway, when I converted my friend, I had asked her if she liked yuri. She was an otaku, but it's *Extremely rare* for a latin otaku to know anything more than what naruto is. (The other day I heard "when it's uke x uke it's called yuri" >_> Damn you narutards...)
So, well, convo was like this
"So, eh, do you like yuri?"
"...Kinda"
"Em, em *trying not to look like a lesbian xD*, I do too, but when it's cute and all the shit"
"So do I!"
"Then you'll be tear-stained after this *shows her touhou doujinshi*"
She loved it a lot, actually. And then it was quite easy to convert her.