Hi Everyone!

I need to disable creating Contacts from pre-chat form. According to the Salesforce documentation it's possible with this code:

embedded_svc.settings.extraPrechatInfo = [{"entityFieldMaps":[{"doCreate":false,"doFind":true,"fieldName":"LastName","isExactMatch":true,"label":"Last Name"},{"doCreate":false,"doFind":true,"fieldName":"FirstName","isExactMatch":true,"label":"First Name"}, {"doCreate":false,"doFind":true,"fieldName":"Email","isExactMatch":true,"label":"Email"}],"entityName":"Contact","saveToTranscript":"Contact","showOnCreate":true}];

I tried it out in my dev org with a visualforce page and in my customer's  sandbox with a dummy website, and it didn't work.  Contacts are still created. However it works for other parameters. E.g. setting "saveToTranscript" to an empty string disables saving contacts to transcript in the Console. 
Does anybody has an idea, how I can disable creating contact, when the pre-chat form is submitted by visitor. 

Thanks in advance!