bloggerapi.module: Error when adding drupal site to MozBlog

Using Mozilla 1.4 + Mozblog 6.20 + Drupal HEAD

I'm getting the following error when trying to add a new blog server in Mozblog (Preferences->MozBlog->Blog Servers):

Fault! <XMP-RPC Fault: (1) Unknown method>

This step is working fine with Drupal 4.2.0.

Here is a HTTP log:

request:

POST http://localhost/tests/drupal/xmlrpc.php HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624
Accept: application/x-shockwave-flash,text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1
Accept-Language: fr-fr,en-us;q=0.7,en;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Proxy-Connection: keep-alive
Content-Type: text/xml
Content-Length: 284
Cookie: style=Black; PHPSESSID=28f96d1a5dfc0d037656531e06c1975d; eZSessionCookie=b10ec24d714e7283eae7f6f6f7707cbc

<?xml version="1.0" encoding="ISO-8859-1"?><methodCall><methodName>blogger.getUsersBlogs</methodName><params><param><value><string></string></value></param><param><value><string>bruno</string></value></param><param><value><string>32ble91</string></value></param></params></methodCall>

response:

HTTP/1.1 200 OK
Date: Sat, 04 Oct 2003 11:40:09 GMT
Server: Apache/1.3.28 (Win32) PHP/4.3.1
X-Powered-By: PHP/4.3.1
Transfer-Encoding: chunked
Content-Type: text/xml
Content-length: 351

15f
<?xml version="1.0"?>
<methodResponse>
<fault>
  <value>
    <struct>
      <member>
        <name>faultCode</name>
        <value><int>1</int></value>
      </member>
      <member>
        <name>faultString</name>
        <value><string>Unknown method</string></value>
      </member>
    </struct>
  </value>
</fault>
</methodResponse>
0

Note also the "15f" characters before the xml tag and the 0 at the end...