PDP-11 emulation on ITS?
I suspect that there's a misunderstanding in the report. SimH is a family of emulators, among which are a single model of the PDP-10 (the KS-10 processor), and the entire family of PDP-11 systems (from the original bare bones PDP-11/20 to the final PDP-11/84 and PDP-11/94, with all the stops in between).
There are cross-system tools for writing PDP-11 software under ITS, but they're intended for running on "real" -11s.
On the other hand, I might have missed something, since my particular interests in ITS are ITS itself, EMACS and Lisp, and I haven't explored far beyond those.