Joomla 3.0 Template - Field Param doesn't accept HTML

I have a Joomla template with custom template fields in my templateDetail.xml. Now I want to have a field for a footer textarea where HTML (a and br-tags) is allowed. If I save the HTML tags in my textarea, they're removed and not outputted:

            <field name="footer" type="textarea" default="Footer Text (HTML)"
                   label="Footer content"
                   description="Content of the footer"
                   filter="html" />

What is wrong with the field or is it a Joomla bug?