Further problem with Duplex Printing in forms

[system administrator_15]

Hi guys
Once again the saga continues i raised a forum question a while ago to which Seth Parker supplied me with a sed command line entry that seems to work on the command line, but as soon as i place it in a script and call it with the sed -F function it fails to work any ideas.
the command is as below.
sed '/^%%BeginFeature/,/^%%EndFeature/d;s/Duplex None/Duplex/g;s/Duplex false/Duplex True/g'

as i say it seems to work correctly when i use on the command line but not when called though a script, am i missing something or being particularly thick today.
the command that calls the script is set out in the .kshrc file and is as follows.

#TK_PRINT="sed -f /tmp/duplexnew | lp -d opsprint_1"
#export TK_PRINT
#export PRINTER=sdprint

i am a bit braindead now looking at this HELP

andrew