yeah all these ways I'm familiar with.
I was thinking, crap whole post is made... Everything is done, butttt I can't click that [Submit] button.. even if I wanted to I'm going to get burned by forum users for being too early.
Perfect situation would be oh wow, the forum allows me to save as draft ? cool idea, I also notice you have this drop down arrow pointing down on the Submit button. Could def be used here, but maybe user can not see there, still perfect position really. Perhaps the drafts could be listed somewhere within the composer. Or a Bring back icon or some such ?