Hello, I am new to authorize.net SIM integration, but have successfully implemented the Cybersource Hosted Order Page which should, by all accounts, be very similar.  

When I use the appropriate keys and values to send the "sample" cfm form to https://test.authorize.net/gateway/transact.dll, it always returns the 99 code and I can't even GET to the Hosted Payment Form.  When I submit the form to https://developer.authorize.net/tools/paramdump/index.php, I see all of my fields there and populated as expected. (Using the most minimal form, I am passing x_login, x_fp_sequence, x_fp_timestamp, x_fp_hash, x_show_form, x_Amount, x_test_request).

I tried to debug this by using the response code 99 tool and always see a generated fingerprint from that tool which is different than what I see when using the same values on my form and dump the output of the fingerprint generated by <cf_hmac...> to the screen.

I found other posts about SIM/Coldfusion problems, but none that say "I got it to work!" - usually it says "I converted my page to php..."  So, has anyone gotten CF to work with the SIM (or at least past the fingerprint error 99 code)? I would love to hear about the magic behind your success.