Kan någon förklara och helst hitta en work-around till att text-arean endast fyller ut cell 1 trots colspan 3 i Internet Explorer?

<code>
<TABLE BORDER="1" width="500">
<TR>
<TD WIDTH="100%">this cell is 100% and should occupy all remaining space</TD>
<TD>this_is_a_cell with_varying_contents</TD>
<TD>this_is_a_cell with_varying_contents</TD>
</TR>
<TR>
<TD COLSPAN="3">
<TEXTAREA STYLE="width:490px;">
this textarea is 490px wide, inside a colspan 3 cell
</TEXTAREA>
</TD>
</TR>
</TABLE>
</code>