[CentOS] vsftp anonymous upload access

I'm trying to set up anonymous ftp using vsftp.  I want to be able to
allow uploads.  The anonymous id is userid "ftp".  The ~ftp/ directory
is actually owned by root, but ~ftp/pub is owned by ftp.

Here's the vsftpd.conf:
    anonymous_enable=YES
    anon_upload_enable=YES
    local_enable=NO
    write_enable=NO
    local_umask=022
    dirmessage_enable=YES
    xferlog_enable=YES
    xferlog_std_format=YES
    userlist_enable=YES
    listen=YES
    tcp_wrappers=YES


I'm able to login to "ftp", and I'm able to "cd pub".  The pub
directory has permissions ownership ftp:ftp and perms of 750 or:
    drwxr-x---  2 ftp ftp 4096 May 14 12:43 /var/ftp/pub

Since I'm logged on as "ftp" I should be able to create the file
inside the directory and write to it.

BTW, I've had this problem whether
   write_enable=YES|NO
and unless I'm misreading the docs, write_enable shouldn't affect
actual uploads.

What am I doing wrong?
   === Al