Customer exit giving date interval using data from DSO

Hi,

i am new to BI platform.

I want pass two dates as an input using customer exit variable.

For these two dates:

First Date:(Start date)

I have to search startdate in data of table of DSO /bic/Azpro_dso00.

THis DSO has start date and end date.

If my input start  date falls in between start and end date then input start date value should be returned as whatver start date is present in DSO by the customer exit.

Last Date (End Date)

I have to search last date in data of table of DSO /bic/Azpro_dso00.

THis DSO has start date and end date.

If my input end date falls in between start and end date then start date corresponding to input end date value in DSO should be returned as start date present in DSO by the customer exit.

Thus my query will work for the dates between start first date and last date given by dso.