Pull Common from TACO Zone Valve or xfrmr for Wifi Tstat

Like a zillion others in this forum, I need a C for my HW RTH9580. I was looking at some schematics for pulling C from the zone valve xfrmr. My wiring looks wrong. My understanding is that the TACO 571 has the xfrmr Common daisy-chained between the middle pins of the 571's and the xfrmr LOAD (R) would run to the Tstats RH pins. Bottom line is that I need a C and not sure how to get their based on my wiring. No extra wires in the system but can pull whatever is needed. Attachment 42861 (http://www.doityourself.com/forum/attachments/thermostatic-controls/42861-pull-common-taco-zone-valve-xfrmr-wifi-tstat-zone-valve-schematic.jpg)