Reg Managerial hierarchy setup on workflows AX2012

Hi,

I have a requirement where I specify spending limits for approval, Which means Manager has $1000 limit, CFO has $10,000 and CEO has no limit.

I defined these under organizational administration ->Setup ->Signing Limits. Then I configured Purchase requisition workflow where I wanted to define this Managerial  hierarchy approval flow. But could not achieve as supposed. Could any one let me know if there is any example that I can refer to in defining the hierarchy which can be set on the workflow as Managerial  hierarchy.

Thanks,

Joseph