I'm not at all aware of the details of your special needs that require you
to use 8.04. Sorry if I confused things for you!

I can, however, offer a workaround that will allow you to shut down Ubuntu
safely. Press and hold Alt and SysReq (may have a slightly different
spelling on some keyboards). Then press in order, waiting until all disk
activity has stopped (a few second) between each, R E I S U B. This closes
all open files and does an orderly and safe shutdown. You will never lose
any data shutting down this way. Just powering off is probably 99% safe but
this is 100% safe.