Authorize.net fails login

Hi, I'm still testing HikaShop but it's been slow going during the holiday season

I've enabled Authorize.net payment for all zones and I get Authorize on the checkout page. When I click the "Next" button on checkout I see a screen flash for a moment and then it goes off to Authorize.net before I can do anything at all. I don't know if that's intentional since it looks like there's a button there to initiate the transaction.

Anyway, Authorize.net comes back with this page:

The following errors have occurred.
(13) The merchant login ID or password is invalid or the account is inactive.

I have created a test account with Authorize.net and put the API key in HikaShop's "Login ID" field - is that correct?
I put the transaction key in its field.
I created an md5 hash string on Authorize.net's site and put that same string in HikaShop's md5 field.
I've tried all four combinations of live/test on HikaShop crossed with live/test on Authorize.net and it's always the same.
Authorize.net's password required mode was enabled by default but disabling it didn't help.

Is it possible they created the test account but didn't activate it?
HikaShop doesn't ask for anything labeled "password". I've been assuming that refers to the API key. Is that correct?

Any ideas?

Doh! (Hand slaps head)

I neglected to change the transaction URL to test.authorize.net. Making that change got me through to their page and I was able to complete the test transaction.

Maybe someone else will find this useful. Otherwise, sorry to waste the bandwidth.

Since you said so I gave it a try. They sent a "Payment Gateway ID" to me in my signup email so I tried that. No good.

I put back the API key and it works again.

Maybe it's different because I'm using the *test* server rather than the official transactions server.