ARCHIVE and HERE are separate arguments. HERE isn't a parameter for the ARCHIVE argument; it's a separate argument in its own right. The docs list the arguments and (if any) their parameters.
ARCHIVE=.7z,single won't work (due to single switching things into a slower method of adding files to archives which the Archives plugin doesn't support), but you can use this as a workaround:
(As a bonus, the workaround is also faster for Zip files, even though it isn't needed for them.)