Access textarea in c#.net

Im begginer in asp.net. 

In my previous project I used ckeditor asp.net control in  content page:

<asp:TextBox ID="CKEditor2" runat="server"  TextMode="multiline" name="Content">

It works well. By this way I could used ckeditor control in c#  and get set a value to this control:

CKEditor2.text="";

But this way doesnt has file browser for uploading images and etc.

In my new website.

I downloaded a file browser in asp.net:

http://www.mikesdotnetting.com/Article/212/A-CKEditor-File-Browser-For-ASP.NET-Web-Pages

This website uses a textarea for ckeditor like:

 <textarea id="CKEditor2" name="Content" ></textarea> 

My problem is that when I using :

<asp:TextBox ID="CKEditor2" runat="server"  TextMode="multiline" name="Content">

The file browser doesnt work and when I using:

 <textarea id="CKEditor2" name="Content" ></textarea> 

File browser works well but I cant access to CKEditor2 in c#.net .

My problem is that when I using :

<asp:TextBox ID="CKEditor2" runat="server"  TextMode="multiline" name="Content">

The file browser doesnt work and when I using:

 <textarea id="CKEditor2" name="Content" ></textarea> 

File browser works well but I cant access to CKEditor2 in c#.net .

Help me, please