Cannot create a new StockTransfer object in SDK DI

I'm having a problem using the V6.7 DI SDK with VB 6.

My code loops through a collection, creating stock transfer entries in SAP BO. The User requirement is to add detail lines to the stock transfer until the from warehouse code changes after which a new stock transfer is created for all items originating from this warehouse, etc.

So I have declared a stock transfer object:

Private SAPStockTransfer As SAPbobsCOM.StockTransfer

Set SAPStockTransfer = SAPCompany.GetBusinessObject(oStockTransfer)

After which I set the appropriate properties of the stock transfer object and add the stock transfer lines as appropriate.

When the warehouse changes I firstly call the add() method of the stock transfer object then I reset the stock transfer object as follows:

Set SAPStockTransfer = Nothing

Set SAPStockTransfer = SAPCompany.GetBusinessObject(oStockTransfer)

The problem is at this stage, the SAPStockTransfer is not re-initialized, as I would have expected, but persists the previously held values.

Am I doing something wrong?