Hi Grippo,
We do not have the -I option available in our man page
I do not know if the version of tar installed has someting to do with the options available
$ lslpp -w /usr/bin/tar
File Fileset Type
----------------------------------------------------------------------------
/usr/bin/tar bos.rte.archive File
$ lslpp -l bos.rte.archive
Fileset Level State Description
----------------------------------------------------------------------------
Path: /usr/lib/objrepos
bos.rte.archive 5.3.0.51 COMMITTED Archive Commands
Path: /etc/objrepos
bos.rte.archive 5.3.0.51 COMMITTED Archive Commands