Hey, thanks everyone. Here's what I did.
I created a themeswitch folder and made two scripts, one for each theme, then I placed them in the menu. This way I can make a bunch of themes and not just two. The script looks like this now.
cp -fr /home/ville/.themes/oma_black/oma /home/ville/.themes/
cp -fr /home/ville/.moc/themes/black/oma /home/ville/.moc/themes
cp -fr /home/ville/.config/terminator/black/config /home/ville/.config/terminator/
nitrogen --set-centered /home/ville/images/wallpapers/oma_black.png
openbox --reconfigure
exit
So, I am basically just copying the themes, it somehow seems more logical for my mind than the renaming. I had a little trouble with the nitrogen, as it doesn't seem to remember what theme I had, so I added this to my autostart.sh:
/home/ville/.themeswitch/white &
...and disabled the previous nitrogen entry there. I thought about making several autostarts so that it would remember which theme I had, but I thought that there's too much hassle if I want to edit autostart later for whichever reason, since I would have to copy/paste the changes to each of my autostarts...
Come to think of it, I could make a script that stays the same for the autostart, though... hmm... maybe I'll do that...
So, what do you guys think? Is this ok, do you see any flaws with this way?
Oh, one thing, I need one more thing to make this work perfectly. When I change the theme, it doesn't update it on any window (pcman, moc, firefox etc). On the thread linked by Iggy they just restarted thunar. Well, first of all, I don't know how to do the same with pcmanfm, and even if I did, it still wouldn't work on firefox or moc or any others... and, even if that worked, it still wouldn't be perfect since it closes the windows instead of changing the themes.
So, what I need is a similar command to the one that the Interface Settings GUI is using to update all the windows with the theme.