Hi,

Firstly, to the developers, thanks for providing such a nice product.  I am a bit of a newbie of a developer, and for the most part I have found uCommerce intuitive and despite its complexity, relatively easy to work with. 

Anyway to business,

I have built a store from the ground up similar to the demo provided.  I have rewritten a lot of it to suit my requirements and it has been working well.  I have however come across a an issue on which I would appreciate some advice. 

I am having trouble with returning to the main shopping cart page after the billing address has been set.  (For example returning to the checkout from shipping methods - (using the same checkout flow process as with the demo store)). 

I can visit this page, but when I try to update the quantities, execute basket pipeline fails and displays an XSLT error.  The Umbraco logs appear to inform me that in a custom pipeline task that i have introduced, the PurchaseOrder object passed to the task is not set to an instance of an object.

The reason that I mention that the problem may be in relation to adding the address is that when I manually remove the billing address Id from the purchase order table, I am able to update / add and remove products as usual.

I could remove the billing address, store it and reintroduce it on submitting to the payment provider (which works), although this really doesn't seem like the right way to do it to me.  

I usually try to figure things out these things myself but in this case I am a bit stumped, any advice appreciated.

Thanks,

Chris