The Kirsten of Visionaire and Revivals indeed looks nothing like the other Kirsten. My normal instinct would be to give her her own page, but I'm somewhat hesitant in this case because all we have of her is two shared covers. I'll let others decide...
russell - it appears that even the Met-Art model pages claim that these two Kirstens are one and the same. However, as you can see from these pictures a Google search gave me (http://www.lustyguide.com/galleries/metart/2005/a56b20440f/index.html), Solaya's partner there is clearly not the Kirsten in, say, Ray of Light.
Sadly, I haven't been able to garner any further information on this other Kirsten.
Unfortunately it's not Kirsten with Solaya in the sets Visionarie and Revivals. It's a shame: Kirsten has absolutely one of the sleekest and gorgeously athletic bodies in the business (not to call the girl in those sets at all unpleasant to look at), she just makes my jaw drop.