Hello again,
unluckily I couldn't made it.
I've made a subclass that inherits QTextEdit and a public function:

getCursorCoordinates() {
QTextCursor *tc = textCursor();
int x = tc->globalX();
int y = tc->globalY();
}

and I had the error:
request for member 'globalX' in 'tc', which is non-class type 'QTextCursor'.

I think because QTextCursor is a private class.

Any other help? I can't upgrade to Qt4..It's not up to me...