Interrobang

I'm writing a document in SGML Docbook (yes, I know I should be using 
XML, but it's one of those legacy things...) in which I use an 
"interrobang," (unicode U+0203D, html &x8253). The process of converting 
the SGML to PDF goes through pdftex, but pdftex doesn't seem to 
understand \Character{8253} and renders it as "<8253>".  I'm reasonably 
sure that the font I'm using contains that character.

More or less guessing what I'm doing, I've done what I think needs to 
happen to incorporate the font I modified to include the 
interrobang--run mktexlsr, updmap-user, and updmap -sys--but the problem 
persists.

So my questions are, is this really because pdftex doesn't understand 
\Character{8253}, and is there anything I can do to increase its 
understanding?

Thanks,
Chris Moller