Well, a friend of mine once used smbclient from the Samba/iX package
to access a floppy disc drive (shared by the PC) from the HP 3000, but
this was just for fun (to see if it works). However, I doubt, that you
could access a CD ROM burner without its special software.
The burner PC might pull data from a Samba/iX share (have done this
to create the Web Starter Kit prototype CD, for example). Or the 3000
might push the files to the PC with smbclient. However, I doubt that
you'd be able to write/port CD burner software to MPE/iX.