Charge Temp not available on MPScan

I am tuning my SBECII TIII and would like to display Charge Temp on my gauges, when I look under Gauge Settings in MPScan the Option of Charge Temp (CHRG) is displayed as a gauge setting, then I go into the actual display layout and I try and select the Charge Temp, but it not an available gauge, only CHGVLT(126) shows up. Does anyone know what this is? On the SBEC and SBECII I was told that the transfer function is identical to the coolant temperature calculation, so you could easily use the same transfer function for both gauges.