[Haskell-cafe] how to use a literal string with bystring useAsCString

Hi, I have a Haskell source file encoded in utf-8. Inside that source, I have literal strings that I'd like to pass to a C function. withCString does the job well until I tried to use the double-quote character ". I get /usr/lib/ghc-6.10.1/ghc: `@: Bad font file format (even when using (chr 34) instead). I didn't understand the reason of this behavior (since the double quote is just ascii) but tried to use useAsCString but coudn't do it. I can ByteString.Char8.pack my string but the problem remains. I tried to use IConv but it uses UTF8.ByteString and I don't know how to make the conversion so I can use useAsCString or withCString. Any idea ? Thanks, Thu