ah yes! you seem to have found a bug. thanks. i have fixed it now. what is supposed to happen is that when you click on the "show ISO3066 list" option, the window that pops up should change the value on your settings when you pick it. this, then, is the way you can find out the secret country code for SITOLand is actually "21".
we have no animosity towards slovenia -- in fact, we like sharing some letters with it. we just want to make sure people can still claim us as their true citizenship if they so desire! haha
thanks again for pointing this out. turns out not to be that off-topic after all!