In the admin guide for MyProxy in the last paragraph, 2nd entry it says:
Add the entries in $GLOBUS_LOCATION/share/myproxy/etc.inetd.conf.modifications to
/etc/inetd.conf or /etc/inet/inetd.conf, or copy
/etc/xinetd.d/myproxy. You'll need to modify the paths in the file
according to your installation.
However, in the MyProxy server that I downloaded (linux-i686-binaries)
there was no $GLOBUS_LOCATION/share/myproxy/etc.xinetd.modifications file.
I think the author probably meant
which does exist, and it works.