Problem importing prefixed custom fields

My question has to do with mapping custom fields that use a non-standard namespace prefix. We’re using Drupal 6, Feeds 6.x-1.0-beta12 and Feeds XPath Parser 6.x-1.12+3-dev.

We’re trying to read feed items into Drupal as nodes including some prefixed custom fields. We know the feed’s ok because we’ve been able to parse the fields using SimplePie in a freestanding application. But when we parse the feed using Feeds and XPath Parser, the nodes are created with the standard fields (title, description, link) but not the prefixed fields or the url attribute of the enclosure field.

Here’s the xml structure:

<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:atom="http://www.w3.org/2005/Atom" xmlns:psg="http://theclientsite.com/psg_namespace" version="2.0">
<channel>
<title>Content Distribution</title>
<link>http://theclientsite.com</link>
<description>Media Distribution Network</description>
<atom:link type="application/rss+xml" rel="self" href="http://theclientsite.com/rss/latest"/>
<item>
<title>Springfield at Arlington North Football</title>
<link>http://theclientsite.com/content/show/31</link>
<description>Springfield Crimson visits Stadium in Arlington to take on the Arlington North Titans</description>
<psg:duration>02:10:06</psg:duration>
<psg:episode>10/12/2012</psg:episode>
<psg:producer>Joe Smith</psg:producer>
<enclosure type="image/jpeg" length="5823" url="http://theclientsite.com/thumbnails/31.jpg"/>
<guid>http://theclientsite.com/content/show/31</guid>
<pubDate>Sat, 13 Oct 2012 21:33:26 -0400</pubDate>
</item>
 </channel>
</rss>

I’m using this mapping:

context: //item
Title: title
Body: description
URL: link
Duration field: psg:duration
Edisode field: psg: episode
Producer field: psg: producer
Image field: enclosure/@url

When I import fresh feed items, the title, description, and link data all import fine but I can’t get it to pull in any of the prefixed custom fields or the url attribute of enclosure.

I’ve searched these forums and tried other options in terms of syntax, but nothing works. I’ve also cleared cache, checked field permissions, tried various contexts and and more. Is there anything I’m missing? On the verge of giving up but I thought I’d give this one more try.

Thanks for any insight you might have.