Auto Enter an integer

I have a field: userid (INTEGER) and I want to attach an Auto Enter value: Creation user id or modification user id.

This is not possible. it only works on TEXT fields.
Is it possible to be fixed?

The userid will not be an integer in all cases, if we make LDAP/Kerberos autenticate possible in future those ID’s are likely not int’s. (thats why we require a text field)