session path: how to?

[Connie]

I know the path
but the server is configured in a way that open basedir restrictions prohibit the use of that tmp-folder

I am struggiling with the hoster to get a functional configuration but they are not very helpful
If I google for that hoster's name and "session path" I find a lot of troubled people

My clients choose this hoster in good trust, for sure, and now they are not very helpful

I will recover from this problem at the weekend and will start again on monday ;=)