[Edit]
I might add that I'm perfectly willing to look into adding this myself if the source code isn't over my head, and/or making it an upstream feature request. I just don't want to re-invent the wheel if someone more knowledgeable about LXDM knows a way to do this already.
Just add a "suspend.desktop" to that folder with an exec line to run your preferred suspend command.
]]>Edit: Nevermind, I saw the question as LXDE not LXDM. For this I have no idea.
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