Open Postbackurl for cross postback in New Window

Hello,

I have a form on which i have a Preview button. The original form uses the Master Page. I am using the public properties on the original page to access the controls on the preview form (Postback Url Page). The for is working fine.

But instead of the postback taking place in the same window i want to open the postback url page in new window, so that user can retain the original form and preview the data in new window. I tried using somthing as below:
Public Shared Sub OpenNewWindow(ByVal Opener As System.Web.UI.WebControls.WebControl, ByVal PagePath As ...