Passing parameters via URL not working.

First, let me say I've looked through all of the similar problems.

I am using Microsoft SQL Server 2012 - 11.0.2100.60 (X64)
 Feb 10 2012 19:39:15
 Copyright (c) Microsoft Corporation
 Standard Edition (64-bit) on Windows NT 6.2 <X64> (Build 9200: ) (Hypervisor)

I create a blank report in Report Builder 3.0 with one Parameter and one text box to display it. 

There are no default values and I've tried it with 'none' for available values and I have tried it using avialable valus of 1 and 2.

I save it to my report server that is running in native mode.

I can run the report just fine using the URL.

But, I've tried passing parameters using both &test=1 and &rp:test=1 at the end of the URL string.

Each time the report simply asks for a parameter and doesn't run.

Is this a server setup issue?  do I need to publish report parts?  What am I missing?

Thanks for your help