jroorda:
If the FTDI chip supplies power I would not try to use both that and an external supply at the same time. It might work if the given Arduino you have is smart enough to switch and only use one supply, but I wouldn't bet on that. If you have the FTDI connected there is really no reason to power the Arduino from the external supply, as it would simply be redundant.
Wow, I'm very embarrassed over actually asking that question 
Just realized how stupid it was. Don't even know why I thought that using the RAW input would be useful in my situation. Have to use my "It was because of the lack of sleep"-card on this one. Many thanks for answering it though!