DoAuthorization before Chained Payment in PayPal API

Question

I am planning to use the PayPal Adaptive Payments API.

I want to do the following:

1) User clicks on 'Authorize' button, a DoAuthorization is done to ensure that the funds are available. User should not be billed at this stage.

2) Some time later (e.g. 3 days) the user clicks on a 'Pay' button, and a Pay command is executed. I know that we can use DoCapture instead, but the problem is that I want to use the Chained Payment method that is only provided with the Pay command.

I have considered doing DoAuthorization > (user clicks on 'Pay' button) > DoVoid > Pay > (Ask user to log into PayPal again). However, it is not good since user has to log into PayPal again. (Or is there a way around this?)

Hence, may I ask if it is possible to link up DoAuthorization with the Pay command? Or are there any alternative ways to achieve the same effect?