here's what i'd like to do

I use the DIBS payment module for zencart, and so far it works fine. what it does is to open at webpage at the paymentservice in the same browser window as the checkout page(final step) in zencart.
what i'd liek it to do is to open at new window(preferbly a popup) and load the payment service in that window.

any idears pointers or the like would be most welcome