Before your text, put spoiler with brackets (like this [ ]) before and after, and then put your text in the middle, and after that put /spoiler (with brackets in front and behind as well)
Panda, don't forget that tables can be great for making a pretty signature! Kayrii's signature no doubt uses a table or two. My one is just made of a simple two-column, one-row table to get the text and spoiler beside the image.
Here it is with the table outline shown to make it easier to visualise:
I tend to miss replies in threads so perhaps send a visitor message, especially on busy threads.
Keep going...
Keep going...
Keep going...
Keep going...
Keep going...
Keep going...
Char. limit reached!
EDIT: Ugh, got scaled down. Does that in the post previews too. You still get the idea though.