I develope this method to mirror the whole house including the annotations for a single family house.
i have three floors (only in architectural plans).
first i go to the basement plan. highlight everything things in the plan and the Filter button appear, and beside it are "save", "load" and "edit buttons.
with all the basement elements including annotations like dimenions highlighted, i pressed the save (beside the words "filter") button, and save the filter as "whole house filter"
next, go to the first floor plan, then go to the "view" tab , "graphics" ribbon and press the "filter" button. now press the "load" button and pick "whole house filter" , now press " add to selection" button, and check the "multiple" check box below, and then highlight everything on the first floor plan including annotations. now press the finish button beside the " multiple"check box and then pick "finish selection"..
go to second floor plan, repeat step in last paragraph.
final step is to load the filter now for "whole house filter" when you are in one of the floor plan, then use the mirror command to mirror entire model.
hope that help.