Oh, big misunderstanding!
FORTI, SERTI and INSP:IR are 3rd-party products especially created for the use with Vienna Suite's Convolution Reverb and/or Hybrid Reverb:
-> http://www.vsl.co.at/en/211/497/1686/1673/115.htm
... they can be considered to be high-quality collections of more or less "conventional" two- or four-channel IRs.
MIR Pro, on the other hand, relies on massive sets of multi impulse responses. All the positioning- and rotation-vodoo as well as the free selection of output formats and main microphone modelling wouldn't work with "ordinary" impulse responses. (... feel invited to read the little primer "Think MIR!" if you're interested in some background information). These sets are organized in so-called "RoomPacks".
Vienna Suite will complement MIR Pro nicely, but the IR-collections for these products aren't interchangeable. To use a slightly silly comparison: It's like the data for simple picture-editing opposed to all the information needed for 3D-animation work.
HTH,