Irec : Adding Salary components to offer

We have following multiple salary components,as standard earning which needs to displayed in the offer letter for an applicant  when rolling out offer and same to be follow to payroll salary component when hiring the employee..

Using salary basis we can attach one salary element, how to we attach multiple salary component to applicant.

We have following standard earning

1. Basis salary

2. HRA

3. Other allowance

How can we acheive this in irec, any guidance or thoughts is highly appreciated 

Thanks

Siva