change out apollo microwave OTR oven

@edatlanta, there is not a cabinet above this oven and no access to the top of the oven. There is small openings at the top of the oven and I can see the four bolts holding the oven to the ceiling, But I have to take the microwave unit out of the housing to get to them...I guess that's how it's done. I cannot find an 24in over the range microwave/convection oven all are over 29+ inches wide. There are 24" microwaves I can use but they lack a light an exhaust fan, so I will need to install a range hood also. My dilemma is how to secure the top of the oven and if the new wall mounts can be installed to any area of the wall and how access the top of the microwave.