My experience in music info or tags in Stereo Tool is minimal and my experience in Proppfrexx is null. But some cursory searches show that Proppfrexx supports Steinberg (VST) plugins. Is there a reason you want to use the Standalone version of Stereo Tool rather than the plugins?
Usually, Proppfrexx manages the tags and music info if using the plugin, if I'm not mistaken.
This is from the feature list on their website "
ProppFrexx ONAIR fully supports almost any VST 2.0/2.4 DSP plug-ins (e.g. StereoTool is even natively supported incl. full RDS integration)."
This is what the manual says "
VST plug-ins (DSPs): Note, that only 64-bit VST 2.4 versions are supported on the 64-bit version of ProppFrexx; and only 32-bit VST 2.4 versions are supported on the 32-bit version of ProppFrexx!"
https://www.proppfrexx.radio42.com/down ... 20v4.0.pdf
Page
85-86 talk about VST plugins.