open new window inside webview within unity

I need to open payment link in webview inside unity. Till here I'm successful using uniwebview plugin for unity. Now after I enter the card details on the payment page, n click pay now, a new page should popup open for entering a password but this popup doesn't open in webview. I need your help to allow this second popup to open as well. Only bid if u have read my description. And mention in your proposal how will you help me tackle this? Budget is fixed 10$-15$ (600-1000Rs)