YES, we are bad, Cyril. And YES, sometimes we don't answer posts around midnight anymore like I do now. (... see, again not a "NO" as an answer. *roll*) To say it quite clearly: It's not my favourite pastime to dedicate _so_ much attention to someone like you who is badmouthing VSL-staff again and again.
Obviously I don't understand what you're asking for (what's "pupitres? desk?" ...?) - or you don't understand what I'm answering.
Of course you can send submixes into MIR (... BTW: every ensemble available as Vienna Instrument is one, actually). Just make sure that you use one of the simplified "General Purpose"-profiles as soon as there is no dedicated Instrument Profile available. Depending on the signal and the chosen settings, the results will be pleasing most of the time, sometimes they will be just so-so, or (in rare cases) simply unusable.
Regards,
/Dietz - Vienna Symphonic Library