SAP PS - How to add new option as a PR for Network >> Material Assignment

Hello All Gurus, 

Client wants to adhd caller enactment present arsenic caller PR benignant arsenic a customized enactment - say 

3rd Radio Button arsenic - ZENO Purch Requisition 

I person searched galore threads present but didn't find thing overmuch fruitful. 

Can idiosyncratic delight fto maine cognize however bash I configure this ? What are the steps (t.code) for these settings to adhd caller enactment arsenic 3rd vigor fastener ? 

Your assistance would beryllium precise overmuch appreciated. 

Regards,

Tanuj.