Hey Henk, yes you can. Currently we do not support changing that setting by managed admin, but feel free to contact with our support and we'll change that on your behalf. Just provide us with all the details in the support case.
In case anyone hits that question:
We have dropped support for that. It is always taken from the browser now. There is no option to override that setting. Previously it caused some inconvenience and was misleading sometimes. This is simple and clear now.