I have a '99 mini STO that has been turtled and Osiris, so yes.
But the only problem with doing it is that the reg on a mini goes into the bottom port on the front block. So you either have to use the gemini front block or put a T fitting on the regular front block so that there is a port for the reg and both LPRs. Mine is done with a gemini front block, but I don't know if any one else has done it. Mine was made special by Leon for Bob "turtle" Long.
If you looked around you local hardware store you could probally find a 1/8 npt T fitting. You would also need a vertical ASA to thread into the T fitting so that the reg could be attached, or you could go with a palmer direct stabalizer (which is what mine has now).
I got this off Unholy here on PBNation, but it was originally one of Bob "turtle" Long's personal guns. It is the only Osiris Leon made that used an e-blade. So it is a one of a kind. Here is a link to the thread about it: