Tracking 2CO payments as a goal in google analytics

This has been driving me crazy for two weeks now.. My paypal payments are tracking fine in analytics but I cannot get 2CO payments to show as converted goals in analytics.

when I go to mysite.com/amember/plugins/payment/twocheckout_r/thanks.php, I see the analytics code in the source code but it's not tracking.

the other issue seems to be that when someone pays with 2CO, sometimes they return to that page but often they return, apparently, to:

mysite.com/checkout/purchase

this URL does not exist on my site...going there creates a 404 error, but according to google analytics, it gets visited about half the time a member uses 2CO to pay.

today, I had two 2CO payments, my log files show both were returned to my site using the /twocheckout_r/thanks.php page...neither show up in GA.

is anyone else successfully tracking 2CO payments in GA and if so, what did you do to do it??

approved URL is /amember/plugins/payment/twocheckout_r/thanks.php and that's where they get returned to...sometimes, according to GA. Everything's been set up for 5 years...it's just the GA goal tracking that is proving a nightmare.

why is the URL checkout/purchase showing up in GA when it doesn't exist, neither on my site nor in my log files?

OK, I've done a couple of days of testing and it seems that /amember/plugins/payment/twocheckout_r/thanks.php is not actually really being called by the twocheckout system.

In fact, in my log files it is shown as a POST, not a GET.

I even embedded an 1x1px image directly onto that page and today I had a 2CO payment and that image was not called at all. If that image is not called, it also means the google analytics javascript is not called and that is why GA has no idea a 2CO payment has been made, hence the goal is not completed.

So I return to my initial question...how do you track 2CO payments in GA?

Has anyone managed to do this? How is it possible that there is only a POST call on my 2CO thanks.php page even though the customer should actually be sitting on that page after completing payment?

Is there something obvious I'm missing?

no, it was using the full http and everything.

I've since had two more 2CO payments and I'm 100% positive that the thanks.php page is never really called...it might just be "pinged" in some way. So the image is never called, the GA javascript is never loaded so that GA can't track the payments.

all I get in my log files is this:

64.128.185.196 - - [12/Oct/2010:05:18:50 -0400] "POST /amember/plugins/payment/twocheckout_r/thanks.php HTTP/1.1" 200 8880 "-" "2Checkout.com-purchase libwww-perl/5.814"

as you see, it's a POST, not a GET. That IP always seems the same too, which means it's 2CO pinging that page, not the users themselves visiting it.

How on earth would I track that in GA??? I could do it using the IP number but apparently GA doesn't allow that type of filtering and I've read it's almost impossible anyway.