I don't know if I can say anything that's not already been said.
12, in our church (Mormon), is a symbol of the authority of God. This is due to the 12 apostles (which lead our church with the prophet), and the 12 tribes of Israel (which we are adopted into through the authority of God). I personally think there's a connection between 12 as a symbol of God's authority and the 12 Houses of the Zodiac.
------(Below is some rich details on how Mormons view 12 in the temple)-----
In Solomon's temple, there was a sacred pool thingy (they call it a molten sea) that was on top of 12 oxen.
"It stood upon twelve oxen, three looking toward the north, and three looking toward the west, and three looking toward the south, and three looking toward the east: and the sea was set above upon them, and all their hinder parts were inward."
-2nd Chronicles 4
In my religion, we practice Baptism for the Dead. I'm bringing this up because we've got a font on 12 marble oxen in the temple:
http://www.moroni10.com/LDS/Temple_Tour/Nauvoo_Temple_Baptistry.jpg
The temple in the link above is the Nauvoo temple, and its a little different than others. In some, they have one stair case, making the font shaped like a key hole. Why? Because the authority of these baptisms, the key to unlocking a great power, lies on top of either A) the 12 tribes of Israel [As we are all part of the 12 tribes], or B) the 12 apostles [since we believe that the order of the 12 apostles is how our Church's authority is restored].