Might as well post this, as I have gone to the trouble to make it.
Basically this Mod turns off the "ask to turn" and the "offer to turn" interactions, effectively you can only get a Vampire through Try For Baby with a Vampire, not asking them to turn you.
I actually made it for brillopad over at MTS, he/she asked for some help with disabling the interactions, and as I actually had to do it to see whether it would work, I uploaded it to the post.
The Mod edits the "Socialization" XML and will conflict with any mod that edits the same. (Which is ALOT of Mods)
It can be got from here: http://modthesims.info/showpost.php?p=3439436&postcount=2