I also do not think you can.
The MB/GPW W7 12v conversion kit comes with a 12 gas gauge but no additional sender.
I have looked at Ron's 12v units and his 12v are matched sets, sender and gauge.
This vender has a 12v gauge but says the sender will work on 6 and 12v applications. http://www.vintagejeepparts.com/categor ... 26-Intake/
There are lots of search pages on this topic.