In my opinion your way of doing things should work. Anyway, if it does not, I could suggest you slightly more complicated way, may be using Win32::API technology. See Formatting win32 printer output discussion on this, Courages comments could shed a light on this.

As a side remark, I suggest you to use "copy /b file.dat lpt2" instead of "type ..." command, because it'll better process binary data.
BTW what error win2k gets to you if you'll try my command from console window?

Best wishes,
Jim