.net - Load The Tabs Dynamically?

i m trying to load the tabs dynamically.(Using AjaxToolKit). Firstly, when i hit button1 on pageload, it loads tab1() (works good) and when i hit button2, itloads up tab2() All these tabs are ascx pages. In tab1 i m loading WebUserControl.ascx. it works okay.

Issues:

1) When you runthe code, first click on button2, it doesn't load tab2 dynamicaly but it does when u hit button1 for the first time.

2) Repetitive clicking on button1 or button2 should load the same tabs next to eachother again and again but it doesn't

3) Thirdly, the main issue is that I m tryin to load another .ascx on loadtab2() which should have webparts in it. I should be able to load an another custom usercontrol into these web parts dynamically. But i m not able to do so.

Here is my code:

Default.aspx
<p>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
</p>

[code]....