Do bear in mind, though, that the VST Expression Maps need the appropriate sample sets loaded, and, in the case of Miroslav (same as with some others), that probably means you’ll need multiple instances of Miroslav, if you want the complete orchestra (but that would be the case with Notion too, I am sure ).
Because Miroslav itself doesn’t actually have any presets with “key-switched” articulations, you have to do it by loading the various articulations, each into its own MIDI channel (i.e. “slot”), then program the VST EXpression Map to trigger the articulations by changing MIDi channels. So that means, inherently, that each instance of Miroslav can hold a maximum of 16 articulations, so you’d probably want one instance of Miroslav per section of the orchestra (like forum member ZeroZero built for the orchestra set in HALion Sonic SE… http://www.steinberg.net/forum/viewtopic.php?f=19&t=13798 ).
All that to say that making a VST EXpression set for the complete Miroslav is no mean task, and would be useless anyways, without also supplying the Miroslav multi presets they are intended for.
I suggest that you take a look at what ZeroZero did for HALion Sonic Orchestra in that forum link (you could even try it out for yourself, using the demo library on the installation discs)… it will certainly give you an overview of what would be needed to do the same thing with Miroslav (except that the VST Expression Maps would be different… those HALion Sonic presets have built-in keyswitches, whereas the presets for Miroslav would require MIDI channel change).