There are couple ways get to the windows object for a browser object.
1. Use Low-level recording which is an option while recording.
2. Restart UFT/QTP without Web addin and then record against the browser, which will be detected as Windows obect. Once the coding for the Windows object is complete Restart UFT/QTP with the Web Add in and test.
3. Get the Browser's title and use title with regular expression in a descriptive programming expression.
title = Browser(''MyBrowser'').GetROProperty(''title'')
Window(''micclass:=Window'', ''text:='' & title & ''.*'').Maximize
Note HP has listed more options in HP Document KM1029497
Document ID: KM1029497
Title: How to use Window methods on Browser?