How to access multiple field templates in another field template and in insert page of asp dynamic data?

Question

Hi,

I am working on asp dynamic data
I am using FormView in my Insert page as following

<asp:FormView runat="server" ID="FormView1">
   <InsertItemTemplate>
<asp:DynamicEntity ID="DynamicEntity1" runat="server" Mode="Insert" 
/>
<asp:LinkButton ID="LinkButton1" runat="server" />
<asp:LinkButton  runat="server"  ID="btnCancel" />
    </InsertItemTemplate>
</asp:FormView>
I am using some existing field templates and some custom field templates.
In my form the following fields are available

[DropDownList1]<br/>
[TextBox1]<br/>
[TextBox2]<br/>
[DropDownList2]<br/>
My requirement is 
1) how to get these object in my insetr page code behind(insert.cs) ?
and
2)I have created field template with DropDownList in this fieldtemplate
I want to access remaing fields objects in this field template.
For example in selectIndexchanged event procedure I want to set values for remaining fields(field templates) 
Can you tel me how to do this ?

Thanks,