Thats why I mentionned the usage of a true backup software...
fbackup/frecover included with HPUX has no equivalent command under unix excep perhaps AIX's mksysb...
fbackup creates a header on each tape for this information, includung how many times the tape has been used... and also a catalogue... and has include/exclude option file etc...

You would have to write a script to put the info you want in a file with the catalogue of what you are going to archive then you have the choice of saving the lot to tape, or to save the first part to tape using a norewind device and append the backup after...