Can V12 use VST plug-ins? There is a great bit of software called PPMulator (rawmaterialsoftware.com) which gives you PPMs displayed on your monitor - but it needs to use a VST plug-in to get the target application to send audio to it.
VST/RTAS/AU are a plugin architectures supported by some (many) high-end audio programs and a few other types of programs. Media100 is not on that list yet (does not currently support a plugin architecture.)
Most of us buy a nice external Dorrough or Benchmark hardware Unit if we need serious metering. The two advantages being: a) they are a LOT easier to read than screen images of meters (remember LCD's have latency) and b) we don't have to buy "updates" every year and a half.