i kno you marked it as solved and have found a work around. thought id add what ive found out though.
as you said emerald --replace in sessions doesnt work.
i found out emerald --replace in ccsm doesnt work.
choosing emerald from fusion-icon works apparently (i couldnt try this one as i cant get fusion-icon to work period on my Ultimate Edition box but i im sure it does work....im glad fusion-icon works fer somebody)
the big thing here though and i have no clue why they did it. the file /usr/bin/compiz is now missing the relevent parts for emerald. it used to say something to the effect of "start emerald if present". now its gone so emerald no longer auto starts. i found a solution though.
in /usr/bin/compiz you will see a section that looks like this
decorator""
decorator args""
if you put emerald between the "" for decorator and --replace between the "" for decorator args. emerald should not autostart when compiz does once again (like it used to). i know this is a little irrelevent since you already found a solution but i thought you still may be interested. now im not saying this will fix it for everyone but it did for me.
its beyond me why the removed the emerald section and instead replaced it with
decorator""
decorator args""
but neglected to put anything in there. i think they couldve left it exactly like it was. also for some crazy reason they removed the driver whitelist and pcid blacklist.
as far as ive found though the only 2 workarounds that work is editing the file /urs/bin/compiz as i stated above or using fusion-icon as you stated. the command section in ccsm under the decorator plugin seems to do nothing at all.
well anywayz thas muh 2 cents.
cheers
-drama