There should really be a way to see what it will look like without having to actually post. But I don't know if there's anything that can be done, since it is probably out of the moderator's hands anyways. I don't know the options this UBB has.
My other comment is this. Under where it says Reged and Posts, I think O.S., RAM, Processor, and mIRC Version should be added. That way, when I post in bug reports and such, they know what operating system, how much RAM is on my computer, my process and speed, and mIRC Version I'm speaking from.