Where is vB_ProfileBlock_VisitorMessaging rendered?

[MediaHound]

Where is the vB_ProfileBlock_VisitorMessaging template rendered? The only reference to that class that I can find is it's class declaration itself:

[dev@localhost forum]$ grep -ir "vB_ProfileBlock_VisitorMessaging" *
includes/class_profileblock.php:class vB_ProfileBlock_VisitorMessaging extends vB_ProfileBlock

I ask because I would like to add a new template hook before the "Post Message" and "Go Advanced" buttons on the Visitor Messages tab of the member page.

Thanks.