Get the pen tool and get busy, i get very fussy about selections so i spend quite some time. Notice that the little holes in the framework are also cut out.
When you have the selection, make sure to make it in to a channel or save the selection for future reference, it can come in handy with masking.
When you have the selection, make sure to make it in to a channel or save the selection for future reference, it can come in handy with masking.