[Flow] Creating Account and own object at once

[Daniel Völkel]

Hi,

I'm actually building my first project with Flow. Unfortunately I got stuck a little bit at the user registration process. 

Within one fluid form, I want to get username, password and some additional data, based on a model. While calling the createAction, I'll get an error saying 
Exception while property mapping for target type "Vendor\xxx\Domain\Model\xxx", at property path "": Object with identity "xxx" not found. 

In the Flow Cookbook, I found an article about Data Transfer Objects and creating multiple objects with one form (unfortunately I'm not allowed to post links). Could this be the solution to my problem or am I on the wrong path?

I hope you can help me.

Best regards,
Dan