On my RHEL4 system i was able to write a KSH script and set enviornment varibales by doing the following:
set +o braceexpand (turns off braces)
CLUSTER_NODES='{"usplselux140","usplselux141"}'
echo $CLUSTER_NODES
{"usplselux140","usplselux141"}
variable is set as wanted and looks like above echo output! I require the enviroment variable to be exactly like the output.

Now i have moved on to Linux 5 and doing the same thing i get the wrong output with braceexpand turned off as in RHEL4.

set +B braceexpand
set -o
Current option settings
braceexpand off
set +o seems to the do the same and turns off braceexpand
but the output of the same above is different.

Output: ksh shell environment settings

CLUSTER_NODES='{"usplselux140","usplselux141"}'
echo $CLUSTER_NODES
"usplselux140" "usplselux141"

It has stripped the brackets and pulled the comma seperator as well. no matter what i do to braceexpand it doesn't come out like i need and it did in RHEL4.

We are running RHEL AS x86_64 OS versions for 4 and 5.

You help is appreciated.