listo ya logre lo que queria era bastante sencillo con un javascript aqui dejo el codigo por si alguien lo llegara a necesitar:
    
Código HTML:
Ver original- <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> 
- function instag(tag){ 
- var input = document.form1.contenido; 
- if(typeof document.selection != 'undefined' && document.selection) { 
- var str = document.selection.createRange().text; 
- input.focus(); 
- var sel = document.selection.createRange(); 
- sel.text = "[" + tag + "]" + str + "[/" +tag+ "]"; 
- sel.select(); 
- return; 
- } 
- else if(typeof input.selectionStart != 'undefined'){ 
- var start = input.selectionStart; 
- var end = input.selectionEnd; 
- var insText = input.value.substring(start, end); 
- input.value = input.value.substr(0, start) + '['+tag+']' + insText + '[/'+tag+']'+ input.value.substr(end); 
- input.focus(); 
- input.setSelectionRange(start+2+tag.length+insText.length+3+tag.length,start+2+tag.length+insText.length+3+tag.length); 
- return; 
- } 
- else{ 
- input.value+=' ['+tag+']Reemplace este texto[/'+tag+']'; 
- return; 
- } 
- } 
- function inslink(){ 
- var input = document.form1.contenido; 
- if(typeof document.selection != 'undefined' && document.selection) { 
- var str = document.selection.createRange().text; 
- input.focus(); 
- var my_link = prompt("Enter URL:","http://"); 
- if (my_link != null) { 
- if(str.length==0){ 
- str=my_link; 
- } 
- var sel = document.selection.createRange(); 
- sel.text = "[a href=\"" + my_link + "\"]" + str + "[/a]"; 
- sel.select(); 
- } 
- return; 
- }else if(typeof input.selectionStart != 'undefined'){ 
- var start = input.selectionStart; 
- var end = input.selectionEnd; 
- var insText = input.value.substring(start, end); 
- var my_link = prompt("Enter URL:","http://"); 
- if (my_link != null) { 
- if(insText.length==0){ 
- insText=my_link; 
- } 
- input.value = input.value.substr(0, start) +"[a href=\"" + my_link +"\"]" + insText + "[/a]"+ input.value.substr(end); 
- input.focus(); 
- input.setSelectionRange(start+11+my_link.length+insText.length+4,start+11+my_link.length+insText.length+4); 
- } 
- return; 
- }else{ 
- var my_link = prompt("Ingresar URL:","http://"); 
- var my_text = prompt("Ingresar el texto del link:",""); 
- input.value+=" [a href=\"" + my_link + "\"]" + my_text + "[/a]"; 
- return; 
- } 
- } 
-   
- <form name="form1" method="post" action=""> 
- <input type="button" name="Submit" value="B" onClick="instag('b')"> 
- <input type="button" name="Submit3" value="U" onClick="instag('u')"> 
- <input type="button" name="Submit4" value=" I " onClick="instag('i')"> 
- <input type="button" name="Submit2" value="LINK" onClick="inslink()"> 
-