Have you tried adding the whole meta tag programmatically?
Once you get the to run server-side, add your new tag dynamically on Page_Load() and you can specify all its attributes.
The process is well described here:
http://www.howtoadvice.com/SetMetaTags
Maybe this code inside the head tag will be what you need:
<%= string.Format("<meta http-equiv='refresh' content='10;url=http://contact.test.net/main.aspx?{0}' />", Request.QueryString.ToString()) %>
However, I wouldn't advise you to do it this way. For example, this URL:
http:/mysite.with.metaredirect?<script>alert('hello!!!')</script>
will throw an exception in asp.net if you haven't disabled its security features, and you never know if someone (or even yourself) will turn those off for some other reason.
A code-behind massage of the querystring is strongly advised!