Localized number

[Roberto Amorim]

Hi.
I know. It's maybe a silly question. But, I'm a newbie.
I trying to convert a number to a localized format using this code.
However, how you can see, it isn't working. 
What am I doing wrong?

static void CCFormInit(FormPtr frmP)
{
 CharPtr ValorFormat;
 FieldPtr fld;

 fld = FrmGetObjectPtr(frmP, FrmGetObjectIndex(frmP, CCLimCredField));
 ValFormat=(CharPtr)Registro->LimCred;
 StrLocalizeNumber((CharPtr)ValFormat, '.', ',');
 FldDrawField(fld);
}

Thanks in advance...
Roberto