I ended up realising that a dsdt.aml got created in the same directory as the DSDT Editor application when I clicked on compile, and so I took this dsdt and used it to boot my SL installation, and my firewire is now working!
I don't know whether this is a bug or I just used the application wrong, but maybe a small pdf file explaining the process would help others not to make the same mistake as me.
In any case, thank you for making a great little app, it made patching my dsdt very simple.
update : sleep issue was fixed by ticking the bottom option in energy saver panel as shown in the image here http://bit.ly/d5rmkI
i think i am fully operational now, woohoo!