WP e-Commerce Customer File Upload

Hello!
How create Wp e-commerce checkout type picture/photo upload?

I added:

wpsc-functions.php
__( ‘pilt’, ‘wpsc’ ) => ‘pilt’

checkout.class.php
case “pilt”:
$output = “<input type=’file’ name=’picture’ id=’picture’ accept=’image/jpeg, image/gif, image/jpg’/>”;
break;

wpsc-user_log_functions.php
case “pilt”:
echo “<pilt name=’picture’>” . $meta_data[$form_field[‘id’]] . “</pilt>”;
break;

I get the error message:
Please enter a valid Lisa pilt.

Thanks in front, Priit