He mentions the Innuendo session during this recent interview:
http://www.guitarplayer.com/rock/1103/steve-howe-examines-his-career-on-anthology/53697
Are there any other recounts of the session?
The Real Wizard
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musicland munich
There might be different recounts, but this one fits more or less the version I know about Howe`s involvement.
Sebastian
There's quite a detailed one on his website (or at least it was there), and I think on a Q&A as well.