Mapping of HR budgetting to Irecruitment vacancy

The Department Manager needs to raise new Vacancy Requisition through IRecruitment module whether it is possible by modifying/customizing the existing Irecruitment Manager responsibility. And please advice how do we do the Manpower budget mapping for headcount budgeted positions.

I have already referred the PUI Vacancy & Requisition form which is done from Core HRMS module. Is it possible to do it through Irecruitment module itself with Budget Mapping for position. 

Thanks
Siva