For Windows OS, the metric is available either through perfmon counters or the WMI (Windows Management Instruments) classes.
To see which perfmon counters are accessible to the netprobe, do the following:
From the cmd, from the netprobe install folder, run this:
NetprobeNT_64.exe -perf > c:\temp\perfmon.log
(change the .exe filename if needed)
This will save all the perfmon counters in the perfmon.log file.
You can investigate the file to see if the virtual memory information is there.
Below is a sample xml that will only show the _Total value: