Google Conversions - Tracking conversion sales with cookies

We are currently using Google Conversion tracking as well as Google Analytics, but would like to implement a way to track actual sales from known conversions.

My original idea was to check for a specific cookie when the user finalizes their payment, and if it's found, save the OrderID and ConversionCode to a database. This idea went up in flames, of course, when I found out that the web server cannot actually access the cookies for conversions.

My next idea is to save 开发者_StackOverflow中文版my own cookie whenever the google conversion cookie is written. The cookie would contain a unique ID, which would make my first idea usable again.

Does anyone see any significant issues with this idea? Is there a more effective way of doing this that I don't know about? I'm still very new to Google tools (and cookies in general), so I could be missing something.

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You can set the order value via the google_conversion_value var in the tracking code. This obviously doesn't help with OrderID tracking, but should help you with your attribution model.

Further details here: http://adwords.google.com/support/aw/bin/answer.py?hl=en&answer=86277