Yes, unfortunately, that will be enough... in CH all they need is to state a reason, and that can be pretty much anything the employer claims. In my case, it was due to reorganizational problems (they shut my department down).
On the certificate, on #10, the employer will have to state whether you were dismissed or if you resign. In case you haven't seen any of those, please follow this link for the employer and employee certificates:
http://www.jobarea.ch/downloads/formulare/arbeitslos/
You might want to check thoroughly what is written on the reference letter though (Zeugnis) to ensure that the employer doesn't let slip any other reason than _operational_.