Virtual II and Integer BASIC

Hi. I use the Virtual II Apple II emulator and I have no problem emulating an Apple IIe, but I have not been able to create/use an Integer BASIC Apple II. I have been using the APPLE2O.ROM file which I think is a correct ROM file for an Integer BASIC Apple II. When I use this ROM image the Virtual II boots to an asterisk "*" prompt and when I try to do a Control-B into Integer BASIC all I see happening is a 'B" and back to the asterisk prompt. It seems that I am not executing the Control-B command, but I am typing Control-B on the keyboard. I must be doing something wrong, but not sure what it is. I would apprecate any help. Thanks.