Putting focus in TEXTAREA in a specific place

Hi guys,
1.
I am having a problem with setting focus in a specific place, I am using "focus()" how can I control where it will make the focus? I mean after how many chars..
2.
I have a textarea and a button, when I press the buttun the value in textarea is textarea value + "A".
Now, it adds "A" only in the end, what I want is that when I will press the button it will add "A" to the place where the cursor is.
For example:
the value in text area is "Cool" and the cursor is here "Co|ol"[| means cursor] the value after I press the button will be "CoolA", and I want it to be "CoAol".
Thanks.

Is this what you're after?
http://weblogs.asp.net/skillet/archive/2005/03/24/395838.aspx

This may actually be closer:
http://alexking.org/blog/2003/06/02/inserting-at-the-cursor-using-javascript/

Ok, for question 1 I found a half solution..works onliy in IE, how can I make it work in FF as well?
this is the full code:
[code]
<script LANGUAGE="Javascript">
var globalCursorPos; // global variabe to keep track of where the cursor was

//sets the global variable to keep track of the cursor position
function setCursorPos() {
  globalCursorPos = getCursorPos(FormPost.Post);
}

//This function returns the index of the cursor location in
//the value of the input text element
//It is important to make sure that the sWeirdString variable contains
//a set of characters that will not be encountered normally in your
//text
function getCursorPos(textElement) {
  //save off the current value to restore it later,
  var sOldText = textElement.value;

//create a range object and save off it's text
  var objRange = document.selection.createRange();
  var sOldRange = objRange.text;

//set this string to a small string that will not normally be encountered
  var sWeirdString = '#%~';

//insert the weirdstring where the cursor is at
  objRange.text = sOldRange + sWeirdString; objRange.moveStart('character', (0 - sOldRange.length - sWeirdString.length));

//save off the new string with the weirdstring in it
  var sNewText = textElement.value;

//set the actual text value back to how it was
  objRange.text = sOldRange;

//look through the new string we saved off and find the location of
//the weirdstring that was inserted and return that value
  for (i=0; i <= sNewText.length; i++) {
    var sTemp = sNewText.substring(i, i + sWeirdString.length);
    if (sTemp == sWeirdString) {
      var cursorPos = (i - sOldRange.length);
      return cursorPos;
    }
  }
}

//this function inserts the input string into the textarea
//where the cursor was at
function insertString(stringToInsert) {
  var firstPart = FormPost.Post.value.substring(0, globalCursorPos);
  var secondPart = FormPost.Post.value.substring(globalCursorPos, FormPost.Post.value.length);
  FormPost.Post.value = firstPart + stringToInsert + secondPart;
}
</SCRIPT>
[/code]
works only in IE =\

and for question 2, no this is not what I am looking for, I am looking for something that will put the cursor and focus textarea, let me show you an example:
textarea value is "Cool"
I want to put the cursor and put focus here "C|ool"
| means cursor, how do I do it?

great link obsidian. thx!