Better late than never - thanks for your feed back.
I ended up attaching 1/2"x2" straight brackets to the underside of the speaker's side panels and extended them out just far enough to catch the base of the panels. To protect the panels at the contact point I attached a piece of HD foam...
The ELS panels on my Ascents have slipped down: 1/2" on the left speaker and about a 1/4" on the right speaker. Sometime ago I e-mailed ML about the condition and was told they were aware of the issue and working on a fix but never heard back. Has anyone had a similar situation and is there a fix?