Leave Encashment design

In Absence management module, i have to implement  Leave Encashment process...

reqiurement is that we have to maintain leave encashment account(residual) after PTO carry over process . If employee want to claim encash from his leave account then there should be self service page where he submit his request and it will go for approval.... once approve then element which hold the Leave request infomation sits in Payroll ... Payroll will process and amount will be paid to employee and his Leave encashement account will be update accordingly...

I read somewhere that this will be possible with OAB moudule ... if any body does this then please share information ....