LXML kills my CDATA sections

I'm batch-converting a lot of XML files, changing their character encodings to UTF-8:

with open(source_filename, "rb") as source:
    tree = etree.parse(source)

    with open(destination_filename, "wb") as destination:
        tree.write(destination, encoding="UTF-8", xml_declaration=True)

Unfortunately, it is destroying my CDATA sections and just escaping them instead.

Source:

<d><![CDATA[áÌÀøÅàùÑÄéú ëÌÄé áÈàÅùÑ éäå''ä ðÄùÑÀôÌÈè <small><small>(ùí ëå èæ)</small></small>

Destination:

<d>בְּרֵאשִׁית כִּי בָאֵשׁ יהו''ה נִשְׁפָּט &lt;small&gt;&lt;small&gt;(שם כו טז)&lt;/small&gt;&lt;/small&gt;

Is there a setting which I can set which will tell it to leave my CDATA sections alone? I'm mainly using LXML to change the character encoding and to write the XML header properly.