Add a parameter via code behind at the link back URL

[fra]

Is it possible to add a paramater at the link back URL, I would need to do it via code behind?
Thanks

[Ray]

You should probably read through this old thread which is pretty relevant. You can probably use a hidden input tag for your extra parameter?

[fra]

Thanks for the reply.

I'm using my own textbox as search box, as you can see at www.pesmonitor.eu

The button click event is:

Protected Sub btnSearch_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles btnSearch.Click
Response.Redirect("~/Search/Search.aspx?Lang=" & strLang & "&zoom_query=" & tbxSearch.Text)
End Sub

And on the page load event of Search.aspx, I use the the code from http://www.wrensoft.com/zoom/support/aspdotnet.html

Basically, I need to keep the parameter Lang="..." in the query string when I click on different result pages. The link back URL is Search.aspx, but it does not include the Lang param I need.
Modifying the language file, as follows

STR_FORM_SEARCHFOR=<input type='hidden' name='Lang' value='EN'>Search for:

does not help.
Is there another way to do it?
Many thanks.