[BB_TX]

The red regulator valve is a different valve just off the opposite side tank, at least on mine. The switch over regulator valve your picture shows is something altogether different. Mine looks different than yours as it has more of a dial selection knob rather than a handle for the switchover. Mine is an auto switch over, not sure about yours.
The switch over valves are available from a number of web sites including makariosrv.com whom I have had successful buys from.