Richard,
For the sake of space, I hope you will accept a link to one of the Will Kinney articles I noted above:
http://www.exorthodoxforchrist.com/t...uagint_-_2.htm
He brings a number of supposed NT-LXX connections under close scrutiny. He shows how John Owen, in his massive commentary on Hebrews, interacts with the LXX material in particular verses.
For those interested, this is Kinney's site:
http://www.geocities.com/brandplucked/articles.html
Steve