PHP Toolkit : Creating an Item Fulfillment record.

Hi,

I am trying to create an item fulfillment record from a sales order record but always receive the message :

[code] => VALID_LINE_ITEM_REQD
[message] => You must have at least one valid line item for this transaction.
[type] => ERROR

Here is the code i've been using, although ive tried changing this around alot and always end up with the same message. We do have Advanced Inventory enabled which I think may be related to the problem?

$initializeRecord = new InitializeRecord();
$initializeRecord->type = 'itemFulfillment';
$initializeRecord->reference = new InitializeRef();
$initializeRecord->reference->internalId = '7787927';
$initializeRecord->reference->type = 'salesOrder';