Thanks for your answer!
Yes I can update normal fields and one of my custom fields… Well, maybe it’s better to take a look at the command retrieving the data first. It looks like this:

$result = $this->proxy->get_entry_list(
$this->sess,
‘Accounts’,
$query,
$orderby,
0,
array(
‘openx_c’,
‘customfield_c’,
‘id’,
‘name’
),
$maxnum,
false
);

I’m trying to retrieve two custom fields: customfield_c and openx_c. The mystery is that I can retrieve customfield_c, but not openx_c.

Any ideas?
Regards,
Mike