If you could add some images of where you need to attach the carport, it would assist our members in providing some ideas. Depending on what type of carport it is, you might fix it to the roof rafters through the eaves lining. I'd imagine you would need to remove the eaves lining and have a look at the roof structure at the mounting points. You would then use a suitable bracket to attach the carport.
We look forward to hearing more about the proposed installation location and offering a solution for your project.