How to fix NULL SID Permissions for files created via NFS?

Question

PHP

1) There is a windows server. Acts as a file storage. On it the NFS server is raised.
2) There is freebsd. It has an NFS client installed. With its help, a folder from windows was mounted - the /mnt/ARM directory
3) A site was raised on freebsd, where, incl. there is a file upload form. Files after downloading end up in this /mnt/ARM

Please tell me why the files and directories that are created by Apache php in /mnt/ARM are written with the rights "www:" (i.e. user "www", group <unknown>), and if you look at them from windows, then there is a "NULL SID" group and not a single checkbox "Allow"? How to fix it?
ps: apache is running as user "www:webmaster".