Just an idea... Why don't you fill your eZ database with product objects generated from this SOAP service and then use a cronjob to update your database regullary?
Then you can use this products with the eZP shop functionality.
Also if you make a call to the SOAP service every time the user adds something to basket, you can have problems due to loss of connectivity or slow connection to the SOAP service.
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Nothing is impossible. Not if you can imagine it!
I checked the code a little more thoroughly and I see, that workflows are impossible in my case. Trigger starts after checking the ObjectID, so I created the new extension for this.
@Marko My approach is to get allways fresh informations.
