Hello,
thanks for your reply David. Here is the solution if somebody needs it:
I found a simple way to get the Fulfillment Order ID of Mnaul Orders using the Module “List Fulfillment Order”. It takes the Object ID of the “New Event”, since this New Event is a new order the Object ID ist the Order ID.
Further I used the Module “Create a Fulfillment for Fulfillment Orders” and used the Output of “List Fulfillment Order” which is the Fulfillment Order ID and Line Items IDs.
These parameters can then be used in “Create a Fulfillment for Fulfillment Orders” to create the fulfillment.
@David_Palac: No need to contact the Shopify Support team. 
