CrossPagePostback in new window...

As you may know to postback a page to another page i..e Cross Page Postback you set the PostBackUrl to the page you would like to post the page to. But what if you would like to post back the page and have it open in a new window. I thought easy just set the forms target before it does the postback and presto. But this is not posible as when you overrides the target the nexttime you postback on that page it will still open in a new window and also as the action of the page is overriden for the Cross page postback to work nothing works anymore.