" I need to add two attachments of detail to my 1120S I am efiling from TurboTax business"
The only way to accomplish this is in the efiling section of the program and there are no guarantees it will work.
The program is designed to upload and attach a file containing an 8453-S that is required for efiling. The two additional attachments that you want to efile can be combined into the same PDF (or image file) as the 8453-S and then uploaded and attached to your return. That entire file should be transmitted along with the rest of the forms in your return.
Again there are no guarantees, but that is the only way to attach and efile any kind of form in the program.
