Using the standard 'create invoice from salesorder' in workflows

[Guido1982]

In short, the code you suggested may work if you get the WEBSERVICE id for each related ID you enter. so for account, assigned user and such: you need to overwrite it to get the webservice ID's. Your approach was to get the native invoice instance and add the product lines through webservice. I think it is best the other way around: get a webservice object and then overwrite with the native invoice object where needed.