I can see all the HALionOne presets in HALion Sonic SE incl. “Cello slow” and “Slow movie strings” both in MediaBay and the VSTi itself (1067 HSSE presets in total).
Following the Steinberg FAQ I also managed to make original HALionOne (661) presets to be visible in Cubase 6 + “VST Sound Collection Vol. 1” + “VST Sound Instrument Set - Synthesizers”, in total 849 presets.
So now I am content (still, “locate” function in HALionOne does not work at all).