I tried the two following codes:
<a href="http://www.fuelly.com/driver/wutzthedeal/cy50a-vip-future-champion" target="_blank"><img src="http://badges.fuelly.com/images/smallsig-us/141826.png" width="115" height="40" alt="Fuelly" title="Share and compare MPG at Fuelly" border="0" style="border
olid #ccc 1px;padding:4px;background:#fff;"/></a>
and
and as you can see, neither is getting it done (both copied directly from fuelly).
EDIT: while 2nd version works in the body of a post, it does not work in the sig, as you can see.