Ticket to a third country with confirmed seat and date

Hi there,

I am flying HK > Shanghai (staying for 5 days) > Amsterdam. I plan to apply for the free-transit-144 hour but they require a ticket to a third country (Amsterdam) with confirmed seat and date. Unless I buy a seat, I won't have one assigned before I do the check-in which is 24 hours before my flight to Amsterdam, so I can only show a confirmation of my flight but not the e-ticket. Is this valid?

Thank you.