Sun to VAx tape transfer?

[Edward_Lee_Whiteside at cup.portal.com]

I'm in the process of modifying some software that will transfer files from
a Vax tape to the Sun in the Vax backup format.  What I need to do is write 
Sun files on the tape such that they are readable in by the Vax in the backup
format.  I have been able to write files in the VMS Copy format using another
program (vmstape), but it doesn't handle the object files.  The vmsbackup 
program only transfers from Vax to Sun (right now).  HAve these programs been
updated to do more or have otheare there other programs in use that
could do the job?