HTML or BBCode?

Hello,

I'm trying to post a sig on my forum using HTML code, but it isn't working even when I allow HTML in both the Admin and the User preferences.

The code is something along the lines of this:
<script type="text/javascript" src="http://www.ffxiah.com/widget.php?q=equip&server=Ragnarok&name=Blindphleb"></script>

Also, I have been able to make custom BBCode tags on other Phpbb3 forums, is this something Forumotion will allow or will I have to pay extra for that?

Thanks in advance,
Blindphleb