afaik, that's not possible. exit 0 is ok, anything else is an error.
Actually it is possible ...
echo TEST = standard output (INFO)
echo TEST 1>&2 = warning output (WARNING) = yellow triangle
exit 1 = error and exit = red cross
In BladeLogic 8.2 SP4, your suggestion simply gives a red cross, rather than the warning triangle. It seems that ANYTHING written to stderr is displayed as a red cross.
There MUST be a reliable way of doing this, as the core BladeLogic product does it - we just need to understand how this might be possible via NSH/BLCLI/Jython.
Only you can manipulate error message, but not warning. It is not supported yet.