Authorize.net SIM Process w/Master Pages using VB.NET returns Error 13 Invalid User

I am trying to use Authorize.net's SIM payment gateway process and am using the base code provided on the developer site. The problem is I am using Master Pages with my site and the hidden field names are getting concatenated with the nested control IDs as an example:

This is what the field should look like:

<input type="hidden" runat="server" name="x_login" id="x_login" />

The output ends up looking like:

<input name="ctl00$MainContent$x_login" type="hidden" id="ctl00_MainContent_x_login" value="MyCode" />

Normally that would not be a problem except Authorize.net is picky about field names apparently since I keep getting Error 13 invalid user. I went through their forums and opened a customer support ticket a week ago, no response other than the automated check our forums email. The closest thing I found on their forums is other people with Master Pages having the same problem with no answers.

I also used their developer response site to check out the values that I am sending them and they all seem to be correct, including the field names. I am at a loss. I can post the entire subset of code but it is the code from their site pasted into my contentholder.

The other work around I have is since my Masterpage already has a form I added these lines of code:

Me.Form.Action = "https://test.authorize.net/gateway/transact.dll"
'Me.Form.Action = "https://developer.authorize.net/tools/paramdump/index.php" This link will show all of the form elements that are submitted开发者_如何学Python.
Me.Form.Method = "Post"

The above lines seem to work properly as the output code looks correct.

Finding no help anywhere else I thought I would ask the people who have not let me down yet.

Here is the answer. After trying a lot of different paths, it is definitely the MasterPage that frags the post to Authorize.net. I tried re-"name"ing the controls among several other things and for time conisderations I gave up trying to resolve the issue and just reformatted the page to not use my masterpage file. I am also building a silverlight e-commerce solution and I am a little concerned that I will not be able to use authorize.net for the same reason.