Modifing Table's COL node - error

Hi all,

I got into this issue and I just wonder if you can verify it and what is your workarround?
Here is a simple Table
<col width="10"/>  
<col width="20"/>
When I'm trying to modify the COL elements via DOM API it gives me the error (insertBefore, removeChild etc.)
The Only thig I could think of was changing its properties' values.

Thank you.