CO11N - User exit - secondary process

dear sir,
i have a problem in confirmation for secondary (control key PP02) operation, some shop floor person doing confirmation entry before goods rec'd entry into particular pruchase orders. i want control by this issue, once purchase order closed for that production order (secondary process) after only confirmed that operation
what settings need to change or how to control this?


1. I am not  sure if there is a standard way of controlling this.
2. Another work around is using the user exit to control this.
CONFPP01            PP order conf.: Determine customer specific default values           
CONFPP02            PP order conf.: Customer specific input checks 1                     
CONFPP03            PP order conf.: Cust. specific check after op. selection             
CONFPP04            PP order conf.: Customer specific input checks 2                     
CONFPP05            PP order conf.: Customer specific enhancements when saving           
CONFPP06            PP Order Confirmations: Actual Data Transfer                         
CONFPP07            Single Screen Entry: Inclusion of User-Defined Subscreens            
the above are the user exits that are available fro the CO11N tcode.
3. we have to take a help of the abaper to write coding fort his.
4. The user exit should be called for the
Order type: XXXX
Routing control key : YYYY
then check the relevant purchase and if it has a GR entry if then allow the colln to perform else give a error message.
5. Let me aslo know if there is a standard way to contrl this/