Make picking wizard, one2many field bug

The "Make picking" wizard of the stock module does not work on web-client 5.0.2 (pickings are not modified) but do work with the gtk client.
(server 5.0, addons 5.0, minimal profile, module stock and its dependencies installed)
I create 2 pickings, 1 with status draft(id:1), the other with status done(id:2).
I select both and apply the "Make picking" wizard.

I've modified stock/wizard/wizard_picking_make.py to get a clue of what is happening:
def _get_value(obj, cursor, user, data, context):
    pool = pooler.get_pool(cursor.dbname)
    picking_obj = pool.get('stock.picking')
    print "_get_value data", data
    picking_ids = picking_obj.search(cursor, user, [
        ('id', 'in', data['ids']),
        ('state', '<>', 'done'),
        ('state', '<>', 'cancel')], context=context)
    print "_get_value picking_ids", picking_ids
    return {'pickings': picking_ids}

def _make_packing(obj, cursor, user, data, context):
    wkf_service = netsvc.LocalService('workflow')
    pool = pooler.get_pool(cursor.dbname)
    picking_obj = pool.get('stock.picking')
    ids = [x[1] for x in data['form']['pickings']]
    print "_make_packing data", data
    print "_make_packing ids", ids
    picking_obj.force_assign(cursor, user, ids)
    picking_obj.action_move(cursor, user, ids)
    for picking_id in ids:
        wkf_service.trg_validate(user, 'stock.picking', picking_id,
                'button_done', cursor)
    return {}

===================================================================
With web client:
_get_value data {'model': 'stock.picking', 'form': {}, 'id': 1, 'report_type': 'pdf', 'ids': [1, 2]}
_get_value picking_ids [1]
_get_value data {'form': {'pickings': [1]}, 'ids': [1, 2], 'report_type': 'pdf', 'model': 'stock.picking', 'id': 1}
_get_value picking_ids [1]
_make_packing data {'form': {'pickings': {}}, 'ids': [1, 2], 'report_type': 'pdf', 'model': 'stock.picking', 'id': 1}
_make_packing ids []
===================================================================
With gtk client:
_get_value data {'model': u'stock.picking', 'form': {}, 'id': 1, 'report_type': 'pdf', 'ids': [1, 2]}
_get_value picking_ids [1]
_make_packing data {'form': {'pickings': [(1, 1, {'origin': False, 'address_id': False, 'backorder_id': False, 'invoice_state': u'none', 'min_date': '2009-09-23 16:23:59', 'state': u'draft', 'date': '2009-09-23 16:23:55', 'name': u'PACK1'})]}, 'ids': [1, 2], 'report_type': 'pdf', 'model': u'stock.picking', 'id': 1}
_make_packing ids [1]