Quota 2006 deduction

Hi Experts,

We a client requirement , to develop a custom web dynro object , enabling users to create leave request. On creating the request a custom infotype say 9001 is updated with a record having the below information

absence type

start date

end date

start time

end time

The underlying custom workfloe for the webdynro , need to update the corresponding quota record in 2006 for this absence request.

Kindly advice if there is any bapi or function module available that will allow me to modify the quota record based on the absence type . start date and end date.

Or please explain how the logic can be designed along with the table.

Thanks,

ANju