update UID and GID on internal usermapper

Hello,

we have a problem with our mapping in Unix and Windows.

First we had only a filesystem exported via CIFS, so on first access usermapper created an entry with a new internal UID/GID.

Now we created another new filesystem exported via CIFS and NFS and so my problem is that everytime a user creates a file via CIFS the file gets UID/GID from usermapper. For our Windows world this is ok, but sadly the UID/GID from usermapper isn't the same the user has on our Unix System. For this for unix those are two different users.

Is there a possibility to match those UID/GID?

If I would update the entry in usermapper somehow will it be a problem for Windows then?

We can't change UID/GID on our Unix systems because these are many hundred systems.

Thank you!