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When the HTLP is called, Ingenious will transmit the iclid (Ingenious Click Id) as a GET-parameter. The HTLP must be able to read the value of the iclid and save it in a cookie on the shop domain, so its value can be passed on with the conversion tag later. Read this article for a PHP-code example how to store the Click-Id.
Example
https://yourshop.com/htlp.html?iclid=#{ICLID}
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