bluff+excanvas cut canvas in half on IE8

[Jose Dinuncio]

Hi,

I'm using bluff (http://bluff.jcoglan.com/) with excanvas and css
blueprint to render a pie chart here: http://fstb.edujose.org/summary

In IE8 it appears cut at half. When I look at the code generated by
the js I see:

<div class="span-6">
<canvas style="MARGIN-TOP: -30px; WIDTH: 230px; HEIGHT: 230px"
id=summaryGraph width="230" height="230">
<DIV style="POSITION: absolute; WIDTH: 300px; HEIGHT: 150px;
OVERFLOW: hidden">
<!-- the rest here .. -->

For some reason the inner div is getting height of 150px. If I change
this value in the developer tool, the graphs renders ok, of course.

My question is, what's happening? How can I affect the height value of
this dynamic-generated inner div?

Thanks.