.net v2 output different ID's from the ones specified

Hello,

i'm having a strange behavior on a webpage that i want to understand, when, where and how to correct this. On .net v1.1.4 this code worked flawlessly:

on code-behind on the datagrid event 'itemdatabound':

ddlist.Attributes.Add("onChange", "dropDownItemChange('" & txtBoxDropDownID.ID & "','" & txtBoxDropDownIndex.ID & "','DataGridActividades__ctl" & (e.Item.ItemIndex + 2).ToString() & "_dropDownestadoInscricao');")

rendered: 

 <select name="DataGridActividades:_ctl2:dropDownestadoInscricao" id="DataGridActividades__ctl2_dropDownestadoInscricao" name="dropDownestadoInscricao"

class="InputStyle"  

onChange="dropDownItemChange('txtBoxDropDownID','txtBoxDropDownIndex','DataGridActividades__ctl2_dropDownestadoInscricao');"

style="background-color:Transparent;border-width:0px;width:130px;">

then on .net v2 the same code renders the following:

 <select name="DataGridActividades$ctl02$dropDownestadoInscricao" id="DataGridActividades_ctl02_dropDownestadoInscricao" name="dropDownestadoInscricao"

class="InputStyle"

onChange="dropDownItemChange('txtBoxDropDownID','txtBoxDropDownIndex','DataGridActividades__ctl2_dropDownestadoInscricao');"

style="background-color:Transparent;border-width:0px;width:130px;">

So this renders a different ID than the one that i specified and on the rendered page it's using a javascript that will get that control from it's ID. That's why it's not working.

Thanks in advance,

Chapas