If you run into any time limit problems or posts getting eaten on any forum or with web-based email, it is always best to compose in Notepad. It is very difficult to lose content typed into Notepad. Then, when your message is ready, you can open the window, paste it in, and post quickly. I put the notepad icon, along with the calculator, down in the lower left quick-launch icons. If shielding what you compose from the slings and arrows of outrageous internet misfortunes is important to you, it's really the only way.
If you're on a Mac, you'll have to figure out the equivalent on your own.