how to add application parameter for WDP ABAP application

Hi,

Am just building a WDP ABAP object where I need to add a application parameter which gives me the "PERNR", please tell me how to add, when am trying to add its not allowing to add the "type".When I click on F4 of Parameters its already showing some exiting para's which only am able to add.

Here I need to add a new one,Plz suggest me to reslove this.

Regards

Rajesh