Creating Payment Plan with Id

Hi there,

In the SOAP API documentation, the following is stated about predefined billing schedules:

When using a predefined billing schedule the number of payments, payment amounts, and payment due dates are calculated based on the selected billing schedule.  

However, CreatePaymentPlan requires you to pass start and end dates, which override those of the billing schedule defined with the id. I've tried passing in empty strings, spaces etc. with no effect.

Is there a way to achieve this without calling GetBillingSchedules, and then passing the start and end dates from that response for my chosen billing schedule?

Thanks,

Patrick.