As noted in this thread: <a href="http://community.logos.com/forums/t/20675.aspx">Finding which Greek words are translated from the Hebrew in LXX - Logos Bible Software Forums</a>

Bible word studies on a Hebrew Lemma should include not only the first prioritized Bible, but the LXX /HEB Rev int as well in a second translation ring.
We do get a separate LXX ring on greek words one for NT one for LXX) We should also get both in the Hebrew BWS as well.