problem writing a string container class

Im having trouble implementing a 'const char *' cast operator along with an indexing operator ('[]'). Everytime I try to compile VC6 gives me a 'two overloads with similar conversions' error.

I'd post code, but I'm ever-so certain its not a code problem. Has anyone encountered a problem like this? Is there any way to suppress the built-in operators, or maybe force the compiler to choose one over the other?

It would be a good idea to post the code... at least the prototypes for the operator overloading functions. According to VC you are breaking the conversion rules for overloading functions and generating ambiguous calls.

Code:

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// .h
operator const char *() const { return myCString; }
char & operator[] (unsigned ind) { return myCString[ind]; }
.
.
.
// .cpp
String str = "ABC";
str[0] = 'X';  // error

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