The Sheltering Sky is the Roland GR-300 in the hands of both Fripp and Belew. The Fripp lead is the typical lead voice (more open freq on the VCO than the Metheny lead) up an octave with slight res to give it that air escaping from a balloon sound. He brings in the GR switch vibrato with the warble set on a high rate (the switch is on the hex bridge of his G-303 guitar, metal ground, momentary on one side and locked on the other). He than switches to "buzz-saw" mode with a second synth pitch in 5ths and the hex distortion. Belew does the same for the close, bringing in the sweep (slow attack VCA) albeit more subtly than the Andy Summers sweep a la "Secret Journey". The live version of this song (search Youtube) is way cooler with the extended dueling Gr's at the end.
People have been trying to get the Gr-300 tone out of the axe (lots of threads, eg. Metheny tone) although it does have a very distinctive sound despite it's simple architecture ( a Jupiter 8 version pitch to VCO would have been super cool, although waaay too expensive). The new synth with the 3rd voice may be able to do this in the II FW 6.0 the trick is to get the fast warble (LFO control of VCF maybe linked to ADSR), than switch to the 5ths, either in one synth block or bring it it in a second block, with a distorted guitar underneath emulating that Hex distortion. I think it can be done to emulate sheltering sky (no exact replica or Metheny lead or the big polyphonic Andy Summers sound) and any truly polyphonic parts would be no go's but one can come close layering effects guitar underneath, particularly with pitch shifters.
My own Gr-300 is not going anywhere, although I am too totally immersed in Axe II fw 6.0 to give it much notice right now.
) they should be sufficient, too. 