Hmmm.
I just tried it, and it worked.
After the preview, the "enable emoticons" was checked again, but the preview did not include the graphics. When I unchecked the box again and posted, it came up with text only.
I think that the forum defaults to enabling emoticons, and will switch it after a preview.
I'll look into modifying it to remember your preference, but no guarantees come with that.
I also just noticed that the text is the wrong color at the bottom of this window. I'll fix that tomorrow.
Mike.