you should delete the MR_extension DLL file from steinberg MR folder(do a search to find them and delete or move them to other location.maybe there are 2 extension dll files cant remember)
now when launching cubase the MR editor should not be grayed and function(but you loose the MR extension in cubase mixer)
alternatively you can uninstall All mr drivers,and install it without the MR_extension from the first place