One transaction across independent web requests

Question

I am developing an OrderComposer library
the use case is as follow:

1-Begin transaction
2-Check the stock          (Page1)
3-Reserve                     (Page1)
4-select delivery way      (Page2)
5-Select payment way    (Page2)
6-Pay                          (Page3)
7-Commit                     (Page4)

My problem is I can not keep the transaction across these page.
I used transactionScope class and it does not working fine.

Also The library is calling another library for Check and reserve items with separate connection to the database

also each action with the database has it's own connection object, which automatically close after finish it's job

any suggestions.