[plt-scheme] Newbie Macro question

Hi there,

I just began to play with define-syntax and I seem to be unable to create a
macro that does this:

>(to-string MyStringToBe)
"MyStringToBe"

The closest I got was this:

(define-syntax to-string
  (syntax-rules ()
    ((_ x) (symbol->string '|x|))))

But this does not preserve case, i.e.

>(to-string MyStringToBe)
"mystringtobe"

altough

(symbol->string '|MyStringToBe|)

returns the desidered result:

"MyStringToBe"

I have a feeling that what I want cannot be done but I do not have a clear
understanding of why. My understanding is that define-syntax creates a
syntax transformer which is applied at "expansion-time" to rewrite usages of
the macro. But I am having trouble undertanding what the macro arguments (x
in the to-string macro) are. I initially thought they were just text tokens,
but the rsult above threw me of.

Would some kind soul care to enlighten me?

Thanks in advance,
-pp