As part of the kitchen remodel (we were just going to fix the ceiling

) we replaced a couple of windows and put in a french-door. We're now looking at replacing the siding on the back of the house since we've killed most of it in the remodel anyway. We want to replace the vinyl with something like a Hardie cementboard siding; however, residing the entire house is not in the budget right now. So, here's the question:
On an outside corner where one side of the house is vinyl and the other cement board can I just use a vinyl corner piece? IOW, the corner piece is for looks only, right? The siding is held in place w/nails across the entire run.