"Edit Service Parameters" broken for operation parameters

I specified the following parameter in service.xml:

<operation name="CheckAvailability" mep="http://www.w3.org/2004/08/wsdl/in-out">
<actionMapping>http://example.com/booking/service/CheckAvailability</actionMapping>

<parameter name="InflowSecurity">
<action>
<items>Timestamp</items>
<timestampStrict>true</timestampStrict>
</action>
</parameter>
</operation>

If I try to edit this parameter using the "Edit Service Parameters" page of the admin console, the HTML is broken. This is the HTML code that is generated for the input field:

<tr>
<td>InflowSecurity</td>
<td><input type="text" value="<parameter name="InflowSecurity">
<action>
<items>Timestamp</items>

<timestampStrict>true</timestampStrict>
</action>
</parameter>"
name="CheckAvailability_InflowSecurity" size="50">
</td>
</tr>

Obviously the opening and closing tags of the element <parameter> should be removed. All that belongs into the value attribute is <action>....</action>.
Also, quotation marks must be escaped if the Rampart configuration contains any XML attributes.