Foo_run environment variable

Do it is possible to add support for envinronment variabile (f.e. %temp%) to foo_run addon?
"%ProgramFiles(x86)%\Mp3tag\Mp3tag.exe" "$directory_path(%path%)"
or
"'%'ProgramFiles(x86)'%'\Mp3tag\Mp3tag.exe" "$directory_path(%path%)"
not work.

see e.g. this thread: