[Zope] ZClass question

[Oscar Picasso]

Hi,

Something that seems maybe very trivial, but I did'nt find the solution.

I have a very simple class ItemId (metatype ItemClass) which is only a
subclass of Image and has no property sheet.

When I try to create a new instance I get the following message : 

Error Type: TypeError
Error Value: argument file was ommitted

Here is my addMethod:

.......
<dtml-with "ItemId.createInObjectManager(REQUEST['id'], REQUEST)">
<dtml-call manage_upload(REQUEST['myimage'])

</dtml-with>
......

Where 'myimage' is the name of a field of type file in my input_addForm.
I works fine when I use manage_upload with an Image but not when it is a ZClass
subclassing an Image. Where am I wrong?

Thanks.