IIRC, I ran into the same problem while writing the Addprinter() UDF. The way I got around it was to shell out and TYPE the file to another file.

Code:
  
shell '%comspec% /c type "$driverinf">%temp%\addprinter.txt'


Once the new file was created readline worked normally. However, you are right, it would be nice to be able to just read the unicode directly.