How to raise events on usercontrols object from .aspx page ?

Hi,
I have a login.ascx control with three controls (LoginName, Password and A Button) , I want to rase a click event on this button from .aspx page because some restriction is there so that I am unable to write any code on .ascx page.
I have assigned value on login name and password from .aspx onload events. but I an facing problem while rasing event on button.
I am showing code that I have written on .aspx page that I have putten onload section.
Public WithEvents btn As Button Public login_ As New TextBox Public pwd_ As New TextBoxlogin_ = CType(ctlSkin.FindControl("txtLoginName"), TextBox)btn_Click(btn, Nothing)
pwd_ = CType(ctlSkin.FindControl("txtLoginPassword"), TextBox) login_.Text = Request.QueryString("login")pwd_.Text = Request.Quer ...