No "Custom" for recurring payments (20090728)

Battling with merging various repositories from Hg - which I've decided I need to do to keep the differences from mounting too much.

Integrating nORM from MUDI2008-parallel, into MUDI2008-mis.

Successfully creates invoices using PMIS for PayPal purchases. Creates an invoice with zero amount for subscription only order.

Having a problem tracking down why PayPal is no longer returning the "Custom" field (which contains our invoice id, cart id etc) and is used by the callback to know which order etc is being dealt with. This was happening yesterday, and isn't happening now - and googling for "getExpressCheckout" and "Custom" doesn't produce anything useful.

Turns out that PP doesn't support the "Custom" field for recurring payment only transactions. Going to have to look at using the PP token (returned from the first PP call) to index a local store of all the information we currently store in the "Custom" field.

Looked at using "SetCustomerBillingAgreement" instead of "SetExpressCheckout" for a recurring payment only transaction, but ignoring it as: 1) The documentation says don't use if for later versions of the API, and 2) It doesn't support the use of "Custom" for recurring payment only transactions.