My solution with the "Branch by Type" template (maybe someone is interested in):
All triggers (except the triggers of "Insert rec_a" and "Insert rec_b") and exits (except "rec_a" and "rec_b" of "Branch by Type") are of datatype "Anything".
The presence of the two "Database Record" elements is not needed and only for better understanding. Actually it is sufficient to set the datatype of the "Branch by Type" exits and the corresponding "Insert rec_a/rec_b" triggers explicit to the datatype of the "Database Recods".
For best results, use the Firefox browser..