Report generation from base64 pdf returned from webservice

We require to call a base64 webservice directly from an OTBI report placed on the Fusion apps springboard, and open the base64 pdf file. Business case is: we have a 3rd party payroll who's providing the pdf payslips via a webservice. We think of preparing an OTBI report that's accessible from Employee self service, once the user opens the report and gives the year-month parameters, the report will call the service, query the base64 data and by the way the related payslip pdf file returning from the service needs to be rendered in OTBI report or downloaded automatically...